LIGNOPHYTA

True roots +; lateral meristems: cork cambium producing cork abaxially, vascular cambium producing phloem abaxially and xylem adaxially.

EXTANT SEED PLANTS/SPERMATOPHYTA

Plant woody, evergreen; nicotinic acid metabolised to trigonelline, (cyanogenesis via tyrosine pathway); primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins derived from (some) sinapyl and particularly coniferyl alcohols, thus containing p-hydroxyphenyl and guaiacyl lignin units, (lignins derived from p-coumaryl alcohol, i.e. S [syringyl] lignin units); true roots present, apex multicellular, xylem exarch, and branching endogenous; arbuscular mycorrhizae +; shoot apical meristem multicellular, interface specific plasmodesmatal network; stem with ectophloic eustele, endodermis 0, xylem endarch, branching exogenous; vascular tissue in t.s. discontinuous by interfascicular regions; vascular cambium + [xylem ("wood") differentiating internally, phloem externally]; wood homoxylous, tracheids and rays alone, tracheid/tracheid pits circular, bordered; mature sieve tube/cell lacking functioning nucleus, plastids with starch grains; phloem fibres +; stem cork cambium superficial, root cork cambium deep seated; leaves with single trace from sympodium ["nodes 1:1"]; stomata ?; leaf vascular bundles collateral; leaves megaphyllous [determinancy evolved first, then ad/abaxial symmetry], spiral, simple, lamina with vein density up to 5 mm/mm² [mean for all non-angiosperms 1.8]; axillary buds associated with at most some leaves; prophylls [including bracteoles] two, lateral; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores, i.e. no distal pore for release of gametes] +, grains mono[ana]sulcate, exine and intine homogeneous; ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development first endo- then exosporic, tube developing from distal end of grain, to ca 2 mm from receptive surface to egg, gametes two, developing after pollination, with cell walls, with many flagellae; female gametophyte endosporic, initially syncytial, walls then surrounding individual nuclei; seeds "large", first cell wall of zygote transverse, embryo straight, endoscopic [suspensor +], short-minute, with morphological dormancy, white, cotyledons 2; plastid transmission maternal; two copies of LEAFY gene, PHY gene duplications [three - [BP [A/N + C/O]] - copies], nrDNA with 5.8S and 5S rDNA in separate clusters; mitochondrial nad1 intron 2 and coxIIi3 intron and trans-spliced introns present.

MAGNOLIOPHYTA

Lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, non-hydrolysable tannins, quercetin and/or kaempferol +, apigenin and/or luteolin scattered, [cyanogenesis in ANITA grade?], S [syringyl] lignin units common, positive Maüle reaction [syringyl:guaiacyl ratio more than 2-2.5:1], and hemicelluloses as xyloglucans; root apical meristem intermediate-open; root vascular tissue oligarch [di- to pentarch], lateral roots arise opposite or immediately to the side of [when diarch] xylem poles; origin of epidermis with no clear pattern [probably from inner layer of root cap], trichoblasts [differentiated root hair-forming cells] 0; shoot apex with tunica-corpus construction, tunica 2-layered; reaction wood ?, with gelatinous fibres; starch grains simple; primary cell wall mostly with pectic polysaccharides, poor in mannans; tracheid:tracheid [end wall] plates with scalariform pitting, wood parenchyma +; sieve tubes enucleate, sieve plate with pores (0.1-)0.5-10< µm across, cytoplasm with P-proteins, cytoplasm not occluding pores of sieve plate, companion cells from same mother cell that gave rise to the sieve tube; sugar transport in phloem passive; nodes unilacunar [1:?]; stomata with ends of guard cells level with pore, paracytic, outer stomatal ledges producing vestibule; leaves petiolate, lamina [formed from the primordial leaf apex], development of venation acropetal, 2ndary veins pinnate, fine venation reticulate, veins (1.7-)4.1(-5.7) mm/mm², endings free; most/all leaves with axillary buds; flowers perfect, pedicellate, polysymmetric, parts spiral [esp. the A], free, numbers unstable, development in general centripetal; P not sharply differentiated, with a single trace, outer members not enclosing the rest of the bud, often smaller than inner members; A many, filament not sharply distinguished from anther, stout, broad, with a single trace, anther introrse, tetrasporangiate, sporangia in two groups of two [dithecal], ± embedded in the filament, with at least outer secondary parietal cells dividing, each theca dehiscing longitudinally by action of hypodermal endothecium, endothecial cells elongated at right angles to long axis of anther; tapetum glandular, binucleate; microspore mother cells in a block, microsporogenesis successive, walls developing by centripetal furrowing; pollen subspherical, tectum continuous or microperforate, ektexine columellar, endexine thin, compact, lamellate only in the apertural regions; nectary 0; G free, several, ascidiate, with postgenital occlusion by secretion, stylulus short, hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, dry [not secretory]; ovules few [?1]/carpel, marginal, anatropous, bitegmic, micropyle endostomal, outer integument 2-3 cells across, often largely subdermal in origin, inner integument 2-3 cells across, often dermal in origin, parietal tissue 1-3 cells across [crassinucellate], nucellar cap?; megasporocyte single, hypodermal, megaspore tetrad linear, functional megaspore chalazal, lacking sporopollenin and cuticle; female gametophyte four-celled [one module, nucleus of egg cell sister to one of the polar nuclei]; P deciduous in fruit; seed exotestal; pollen binucleate at dispersal, trinucleate eventually, germinating in less than 3 hours, pollination siphonogamous, tube elongated, growing at 80-600 µm/hour, with pectic outer wall, callose inner wall and callose plugs, growing between cells, penetration of ovules via micropyle [porogamous] within ca 18 hours, distance to first ovule 1.1.-2.1 mm, tube moves between nucellar cells; double fertilisation +, endosperm diploid, cellular [micropylar and chalazal domains develop diffently, first division oblique, micropylar end initially with a single large cell, divisions uniseriate, chalazal cell smaller, divisions in several planes], copious, oily and/or proteinaceous, embryo cellular ab initio, minute; germination hypogeal, seedlings/young plants sympodial; Arabidopsis-type telomeres [(TTTAGGG)_n]; whole genome duplication, ndhB gene 21 codons enlarged at the 5' end, single copy of LEAFY and RPB2 gene, knox genes extensively duplicated [A1-A4], AP1/FUL gene, paleo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and three copies of the PHY gene, [PHYB [PHYA + PHYC]].

Evolution. Possible apomorphies for flowering plants are in bold. Note that the actual level to which many of these features, particularly the more cryptic ones, should be assigned is unclear. This is because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied, there is considerable homoplasy as well as variation within and between families of the ANITA grade in particular for several of these characters, and also because details of relationships among gymnosperms will affect the level at which some of these characters are pegged. For example, if reticulate-perforate pollen is optimized to the next node on the tree (see Friis et al. 2009 for a discussion), it effectively makes the pollen morphology of the common ancestor of all angiosperms ambiguous... For other features such as details of sugar transport in the phloem, their placement on the tree is frankly speculative. Finally, for features such as parietal tissue/a nucellus only one (Nymphaeales) to three cells thick above the embryo sac and a stylar canal lacking an epidermal layer, although plesiomorphous for basal grade angiosperms (Williams 2009), I am unsure where on the tree a thicker nucellus and a stylar epidermal layer are acquired.

[NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]]: vessels +, elements with elongated scalariform perforation plates; wood fibres +; axial parenchyma diffuse or diffuse-in-aggregates; tectum reticulate-perforate [here?]; ?genome duplication; "DEAER" motif in AP3 and PI genes lost, gaps in these genes.

VITALES + ROSIDS / ROSIDAE: anthers articulated [± dorsifixed, transition to filament narrow, connective thin].

OXALIDALES + MALPIGHIALES: ?

MALPIGHIALES Martius  Main Tree, Synapomorphies.

Vessel element type?; (sieve tubes with non-dispersive protein bodies); lamina margin toothed [teeth with a single vein running into a congested ± deciduous apex]; stigma dry. - 39 families, 716 genera, 15935 species.

Evolution. Crown Malpighiales probably diverged some time in the Cretaceous-late Aptian, perhaps some 114 million years before present ([119.4-]113.8[-110.7]/[105.9-]101.6[-101.1] million years before present - high and low estimates: Davis et al. 2005a); diversification seems to have been rapid. Other estimates are rather younger. The age of crown group Malpighiales was estimated as (93-)92, 90(-89) million years (two penalized likelihood dates), the stem group age being (107-)103(-99) and (95-)91(-87) million years; Bayesian relaxed clock estimates were slightly older, to 106 and 112 million years respectively (Wang et al. 2009). Wikström et al. (2001) suggested an age for the stem group of some (91-)88(-85) million years, and for the crown group some (80-)77(-74) million years before present, nevertheless, stem groups of many families were evident before the beginning of the Tertiary. Magallón and Castillo (2009) estimated ages of ca 89.3 million years for both relaxed and constrained penalized likelihood datings for the divergence of crown Malpighiales, 98.6 and 98.8 million years for stem Malpighiales (Celastrales are sister to Malpighiales).

The order contains ca 7.8% eudicot diversity (Magallón et al. 1999) and is particularly important in tropical rainforests where it is an important component of the diversity of the understorey; it accounts for up to some 28% of the species and 38% of the total stems (Davis et al. 2005a). Members of Ericales are the other main component of this vegetation.

Caterpillars of outgroups to Nymphalidae-Nymphalinae, -Melitaeini, etc., are quite common on Mapighiales (Nylin & Wahlberg 2008). The butterfly Cymothoë has hosts widely scattered in this order (Ackery 1988), although also found on Bignoniaceae (one species) and Rhamnaceae (sometimes another species). Phyllonorycter leaf-mining moths (Lepidoptera-Gracillariidae - Phyllocnistinae) seem to have diversified on this clade (and especially Fagales) some time in the region of 50.8-27.3 million years before present, well after the Malpighiales diversified, and after the genus itself evolved, some 76.3-50.3 million years before present (Lopez-Vaamonde et al. 2006).

Chemistry, Morphology, etc. Paracytic stomata may characterise a sizeable clade in Malpighiales, and three-carpellate gynoecia are known friom many families. Articulation of the pedicels is another feature that may be common to the order. The atpF gene has been lost several times in Malpighiales, alone among angiosperms, however, details of its distribution remain unclear due to poor sampling and lack of phylogenetic resolution in the clade (Daniell et al. 2008).

See Endress and Matthews (2006b) for petal appendages, etc., in the order, also Matthews and Endress (2008) discuss other floral variation; Tokuoka and Tobe (2006) integrate testa anatomy and embryology with phylogeny.

Phylogeny. Although Malpighiales are strongly supported as being monophyletic (e.g. Davis et al. 2005a; Wurdack & Davis 2009), relationships within them are still poorly understood (e.g. Soltis et al. 2007a). Those in the tree shown here are mostly taken from Litt and Chase (1999), Schwarzbach and Ricklefs (2000), Chase et al. (2002), and Davis and Chase (2004), but they are in general agreement with relationships apparent in broader studies. Davis et al. (2005a) have recently clarified some relationships in Malpighiales in a four-gene (all three compartments) analysis, in particular suggesting an association between the families with parietal placentation (and also Goupiaceae) and that Centroplacus should be recognised as a separate family (see also Korotkova et al. 2009 for relationships in Malpighiales). The inclusion of Rafflesiaceae in Malpighiales follows the recent findings of Barkman et al. (2004, 2007), Davis and Wurdack (2004), and in particular Davis et al. (2006), who place it with strong support as sister to Euphorbiaceae s. str. It seems useful to adopt a narrow circumscription for families that used to be included in Flacourtiaceae and Euphorbiaceae s.l. even if future work suggests reaggregation of genera that used to be placed in these two families, groupings recognized will be different from those suggested by previous classifications. In particular the realignments caused by the break-up of the old Flacourtiaceae and integration with Salicaceae and Achariaceae correlate well with a number of morphological and anatomical characters, although details of character evolution in that clade remain unclear (Wurdack & Davis 2009). In this latter study there is indeed more detailed resolution within the Violaceae-Achariaceae area (see also Korotkova et al. 2009), and also in the Bonnetiaceae-Podostemaceae clade, Calophyllaceae being recognized, Ctenolophonaceae are linked with Erythroxylaceae and Rhizophoraceae, Bhesa with Centroplacaceae, etc. Overall, there are still nine clades containing two or more families and seven separate families forming a very substantial basal polytomy in the order (Wurdack & Davis 2009). Wang et al. (2009) found that Ochnaceae grouped with [Irvingiaceae + Clusiaceae, etc.], although support was very weak; the latter relationship had only 59% bootstrap.

On the other hand, support for the [Balanopaceae [[Trigoniaceae + Dichapetalaceae] [Chrysobalanaceae + Euphroniaceae]]] clade is strong, e.g. Davis et al. (2005a), Tokuoka and Tobe (2006), Soltis et al. (2007a) and Korotkova et al. (2009: 89% jacknife). There was some support for Picrodendraceae as sister to this clade in Soltis et al. (2007a: as Pseudanthaceae, Phyllanthaceae not included).

Includes Achariaceae, Balanopaceae, Bhesa, Bonnetiaceae, Calophyllaceae, Caryocaraceae, Centroplacaceae, Chrysobalanaceae, Clusiaceae, Ctenolophonaceae, Dichapetalaceae, Elatinaceae, Erythroxylaceae, Euphorbiaceae, Euphroniaceae, Goupiaceae, Humiriaceae, Hypericaceae, Irvingiaceae, Ixonanthaceae, Lacistemataceae, Linaceae, Lophopyxidaceae, Malpighiaceae, Malesherbiaceae (= Passifloraceae-Malesherboideae), Medusagynaceae, Ochnaceae, Pandaceae, Passifloraceae, Peraceae, Phyllanthaceae, Picrodendraceae, Podostemaceae, Putranjivaceae, Quiinaceae, Rafflesiaceae, Rhizophoraceae, Salicaceae, Trigoniaceae, Turneraceae (= Passifloraceae-Turneroideae), Violaceae.

Synonymy: Balanopales Engler, Chailletiales Link, Chrysobalanales Reveal & Doweld, Elatinales Nakai, Erythroxylales link, Euphorbiales Lindley, Flacourtiales Heinze, Garciniales de Candolle, Homaliales Bromhead, Huales Doweld, Hypericales Dumortier, Irvingiales Doweld, Lacistematales Baskerville, Linales Baskerville, Malesherbiales D. Don, Rafflesiales Oliver, Marathrales Dumortier, Medusagynales Reveal & Doweld, Ochnales Reveal, Pandales Engler & Gilg, Passiflorales Dumortier, Phyllanthales Doweld, Podostemales Lindley, Rhizophorales Reveal & Doweld, Salicales Lindley, Samydales Dumortier, Sauvagesiales Lindley, Scyphostegiales Croizat, Stilaginales C. Agardh, Turnerales Dumortier, Violales Perleb - Euphorbianae Reveal, Ochnanae Doweld, Podostemanae Reveal, Rafflesianae Reveal, Rhizophoranae Reveal & Doweld, Violanae Reveal - Malpighiopsida Bartling, Passifloropsida Brongniart, Podostemopsida G. Cusset & C. Cusset, Salicopsida Bartling, Violopsida Brongniart

[Achariaceae [Goupiaceae [Violaceae + Passifloraceae] [Lacistemataceae + Salicaceae]]]: crystals in ray cells; sieve tubes with non-dispersive protein bodies; cuticle waxes usu. 0; (foliar glands +); pedicels articulated; nectariferous tissue; stamens = and opposite sepals; G with median member abaxial, placentation parietal, placentae raised; seed arillate; endotegmen persistent; endosperm persistent, oily.

Evolution. All six major clades in this group (Malesherbiaceae + Turneraceae + Passifloraceae make a single clade) may have diverged in the Cretaceous-Albian 111-100 million years before present, or somewhat later (Davis et al. 2005a, details are given for the individual clades: Wikström et al. 2001 suggests many of the clades do not diverge until [well] after 63 million years before present). Larvae of butterflies such as Nymphalidae-Acraeinae and N.-Nymphalinae-Heliconiini, -Vagrantini and -Argynnini commonly eat members of this group (Ehrlich & Raven 1964; see also Dahlgren & van Wyk 1988; Arbo 2006; Simonsen 2006; Silva-Brandão et al. 2008; Nylin & Wahlberg 2008; etc.); this is also discussed under individual families below. Some Acraeinae in particular may cue on the presence of the cyanogenic glucoside gynocardin in potential food plants, indeed, that larvae of Acraea horta, normally living on the woody Kiggelaria africana, ate herbaceous Achariaceae prompted the successfull search for that compound in the latter family (Steyn et al. 2002). Toxic compounds like gynocardin may be sequestered by the larva and passed on to the adult. Interestingly, given the relationships evident in Wurdack and Davis (2008), the distinctive cyclopentenoid glycosides seem to have evolved more than once.

Chemistry, Morphology, etc. There are numerous anatomical, chemical and floral links between Salicaceae, Achariaceae and Violaceae, sometimes also Passifloraceae, Malesherbiaceae and Turneraceae (Nandi et al. 1998). Thus Achariaceae and Passifloraceae s.l. have in common cyclopentenoid cyanogenic glucosides and/or cyclopentenyl fatty acids and also commonly some sort of corona or scales on petals.

There is much information on seed anatomy in Takhtajan (1992) while Krosnick et al. (2006) briefly discuss the evolution of polyandry in this group - in some cases, at least, the numerous stamens form a single whorl.

Phylogeny. Molecular evidence that the whole group of families with parietal placentation and (often) three carpels is monophyletic was initially not compelling (e.g. see Savolainen et al. 2000a; Chase et al. 2002), although part of the rpS 16 gene is absent from Passifloraceae s. str., Violaceae, Salicaceae s. str., and Turneraceae (and also Linaceae and Malpighiaceae, so really a feature of Malpighiales?: see Downie & Palmer 1992). Salicaceae are weakly associated with Passifloraceae, and in turn with Humiriaceae and Pandaceae, and Violaceae are weakly associated with Achariaceae (and Goupiaceae, Lacistemataceae and Ctenolophonaceae) in Chase et al (2002). Tokuoka and Tobe (2006) found a weakly-supported relationship between the Passifloraceae group and Violaceae (see also Soltis et al. 2007a), and strongly supported relationships between Lacistemataceae and Salicaceae. However, Davis et al. (2005a) found a moderately supported association of these taxa with parietal placentation (59% bootstrap, 1.00 posterior probability), and also Goupiaceae, with axile placentation, and a similar grouping is also evident in e.g. Wikström et al. (2001) and Korotkova et al. (2009: 83% jacknife, 1.00 pp, Goupiaceae not included). Ixonanthes was rather surprisingly embedded in Achariaceae in the Bayesian analysis of Soltis et al. (2007a), but that was due to the misidentification of the material examined, which was a species of Hydnocarpus (K. Wurdack, pers. comm.).

Previous Relationships. Classical morphological studies had been suggesting groupings of these families, in part because of their common possession of parietal placentation, appendages in the flower, nectaries outside the stamens, etc. Furthermore, it was known that within the old Flacourtiaceae there were two rather different kinds of seed coat (Corner 1976). It was commonly agreed that Salicaceae were simply an extreme morphology reflecting the wind pollination common in that family, and they clearly could be linked with some Flacourtiaceae. It was also commonly agreed that Flacourtiaceae presented major taxonomic problems. "Flacourtiaceae as a family is only a fiction; only the tribes are homogeneous" (Hermann Sleumer, the monographer of the family, in Miller 1975: 79). Indeed, it was a fiction. Some of the old Flacourtiaceae are now in Achariaceae, a few in Lacistemataceae, while Flacourtiaceae-Berberidopsideae are in Berberidopsidales (as Berberidopsidaceae) and Aphloia (Aphloiaceae) is in Crossosomatales. The remainder of Flacourtiaceae are here, but the name Flacourtiaceae is now no longer in use. Variation in chemistry, leaf teeth, floral morphology, and seed coat anatomy is largely correlated with this division.

ACHARIACEAE Harms, nom. cons.   Back to Malpighiales

Shrubs to trees ((climbing) herbs); cyclopentenoid cyanogenic glucosides and/or cyclopentenyl fatty acids +, gynocardin, ellagic acid [Kiggelaria] +; vessel elements with simple or scalariform perforation plates; fibres septate; axial parenchyma usu. 0; ray cells with scalariform perforations [?distribution]; petiole bundle annular, with two lateral/adaxial strands (inverted medullary plate - Lindackeria); ?stomata; leaves spiral or two-ranked, margins entire (serrate; stipules 0), petiole often geniculate; (plant dioecious); inflorescence spicate or cymose (fasciculate); K and C spiral or not, not in a simple alternating relationship, K 2-5, C 4-15 (3-4, connate - Acharieae), often in two series, (adaxial scales +); (nectary 0); A 5-many, opposite petals or irregular, initiation centripetal or simultaneous, (from a ring meristem), anthers basifixed, elongate (barely so - Chiangodendron; dehiscing by pores; locellate); pollen also tricolporoidate; G [2-10], median member?, style (short), branched or not, stigma capitate-peltate; ovules sessile, (straight - Xylotheca, Hydnocarpus, Lindackeria; 1/carpel), (megaspore mother cells 2 - Caloncoba), integuments 5-6 cell layers across, (outer integument lobed), micropyle endo- or bistomal or zigzag, nucellar cap and epistase +, ring/cap of tracheids in chalaza; embryo sac (Allium-type [bisporic, 8-nucleate] - Acharieae), penetrating chalaza, formin a caecum below tracheids; fruit also a berry; seed (arillate), coat thick, pachychalazal [not Hydnocarpus laurifolius], or both integuments multiplicative [possibly simply different interpretations], testa vascularized, sarcotestal and with stomata (Acharieae) or not, (inner mesotesta sclereidal), endotesta lignified, cells sclereidal (radially elongated), exotestal cells elongated, sclereidal; endosperm copious, suspensor 0, embryo green; n = 10, 12, 23.

30[list]/145: Hydnocarpus (40). Pantropical. (map: from Sleumer 1954, 1980; Şerban Procheŝ, pers. comm. [Africa]; Andrew Ford, pers. comm. [Australia])[Photo - Flower, Fruit, Fruit, Acharia tragodes - Leaves.]

• Achariaceae can be recognised by their stipulate leaves, often entire leaf blades and pulvinate petioles, and flowers in which the number of sepals and petals is often clearly not the same, and/or the perianth is not simply biseriate, and/or the petals have basal, adaxial scales. There is no nectary, and the anthers are usually long. The fruits are often quite large, the placentation is parietal, and the seeds often have conspicuous vascular bundles in the coat.

Evolution. The feeding behaviour of Acraeini butterfly larvae are consistent with the expanded family limits adopted here (Steyn et al. 2002, 2003 and references). Species of Ryparosa consistently produce food bodies, and in a number there are associations of varying closeness with ants (Webber et al. 2007).

Chemistry, Morphology, etc. Gynocardin is found in some other families of this group (Webber & Miller 2008). There are large and medium intervascular pits; the wood also has solitary pores and lacks tracheids. Lindackeria has superficial cork cambium. Pollen variation is considerable (Wendt 1988).

Information is taken from Hegnauer (1966, 1989, as Flacourtiaceae: chemistry), van Heel (1977, 1979: testa anatomy), Endress and Voser (1975: floral development), Miller (1975: wood anatomy), Spencer and Seigler (1985: chemistry), Lemke (1988), Gavrilova (1998: pollen), Steyn et al. (2002a, b, 2003: ovule development, testa anatomy) and Groppo et al. (2010: general); see also Judd (1997a) and especially Chase et al. (2002). Bernhard and Endress (1999) discuss androecial initiation. I thank Sue Zmarzty for comments.

Phylogeny. For the circumscription of Achariaceae, see Chase et al. (2002) and Sosa et al. (2003): Acharieae (more or less herbaceous and viny; no testal bundles; zig-zag micropyle; fibrous exotegmen), Erythrospermeae (Erythrospermum - fibrous exotegmen), Pangieae (inc. Kiggelarieae) and Lindackerieae (Oncobeae minus Oncoba). Note that the family is divided into three strongly-supported clades, largely Hydnocarpus, Erythrospermeae + Lindackerieae, and Acharieae + Pangieae, and support for monophyly of the family as a whole is strong (Sosa et al. 2003), Groppo et al. (2010) questioned some tribal limits in the family.

Previous Relationships. The bulk of Achariaceae have almost universally been included in Flacourtiaceae s.l. (Cronquist 1981; Takhtajan 1997) = Salicaceae, q.v.

Synonymy: Erythrospermaceae Doweld, Kiggelariaceae Link, Pangiaceae Endlicher

[Goupiaceae [Violaceae + Passifloraceae]] [Lacistemataceae + Salicaceae]]: ?

GOUPIACEAE Miers   Back to Malpighiales

Evergreen trees; plants Al-accumulators, otherwise chemistry unknown; vessel elements with scalariform perforation plates; nodes ?; petiole with ± annular bundle(s), plus inverted medullary bundles; branched sclereids +; hairs thick-walled with pitted bases; cuticle waxes 0; stomata laterocytic; leaves two-ranked, tooth ?type, 2ndary veins actinodromous, 3ary veins scalariform; inflorescences axillary, umbellate, pedicel articulation?; C induplicate-valvate, long, apical part inflexed; nectary annular; connective shortly prolonged, with long hairs; pollen with endexinal folds; G opposite petals, placentation axile, several basal ovules/carpel, styluli short, on outer shoulders of carpels, stigmas subulate, type?; fruit a drupe; testa and tegmen ca 6 cells thick, testa with one layer [mesotestal] of sclereids, exotegmen poorly developed; endosperm copious; n = ?

1/2. Central and N. South America (data from Tropicos xii.2010).

• Goupiaceae may be recognised by their two-ranked stipulate leaves with ascending secondary veins and scalariform tertiaries. The inflorescence is umbellate and the petals are relatively long and inflexed at the apex. The gynoecium has basal-axile placentation and widely separated styles; the fruit is a single-seeded drupe.

Chemistry, Morphology, etc. The family is poorly known. It is often suggested that only seedlings have dentate leaves, those of the adult being entire, but leaves of flowering specimens are in fact frequently toothed.

Information on pollen is taken from Lobreau-Callen (1980), anatomy from de Hartog and Baas (1978), and on seed, from Takhtajan (2000).

Previous Relationships. Cronquist (1981) included Goupiaceae in Celastraceae, Takhtajan (1997) in Celastrales, A.-L. de Jussieu and others have placed it in Rhamnaceae.

Violaceae + Passifloraceae: ?

VIOLACEAE Batsch, nom. cons.   Back to Malpighiales

Vessel elements with simple or scalariform perforation plates; calcium oxalate often as crystals; petiole bundles arcuate; stomata para- or anisocytic; pedicels articulated; K quincuncial; A with abaxial nectary; G [3]; K persistent in fruit; exotesta subpalisade to tabular, ± thickened, (mesotesta sclerenchymatous), endotesta usu. crystalliferous. [Anatomical characters unknown for Fusipermoideae.]

23[list]/800. World-wide (map: from Hultén 1958, 1971; George 1982; Hultén & Fries 1986; Hekking 1988 - incomplete for South America).

1. Fusipermoideae Hekking

C contorted, disc fleshy, annular, 5-lobed, filaments adnate to inner surface at indentations; A with paired fringed apical scales, thecae cordate/trapezoid, confluent apically?; capsule ca 2 mm long; seeds arillate/carunculate; n = ?

1/3. Panama, Columbia, Peru.

2. Violoideae Beilschmied

Herbs to trees (lianes); plants often Al accumulators; (cylcotide proteins +), tannins 0 [woody members?]; vessel elements with simple or scalariform perforation plates; calcium oxalate often as crystals; petiole bundles arcuate; stomata para- or anisocytic; leaves spiral or two-ranked (opposite), margins involute, colleters +, (stipules petiolar; lobed); flowers poly- or monosymmetric, (papilionoid); C quincuncial, abaxial C spurred or not; A (3), all or 2 abaxial nectariferous, (filaments connate), anthers connivent, (thecae horizontal), connectives prolonged (± 0); G [(2-5)], micropyle zigzag (endostomal), hypostase +, styles separate or style +, stigmatic head subcapitate, asymmetrical or not, receptive area small; (fruit a berry, nutlike); seeds (winged) often arillate/carunculate, (mesotesta sclerenchymatous); embryo (small), green [Viola]; n = 6(?plesiomorphic)-13+.

22/795: Viola (400-600: cleistogamy widespread, V. tricolor, the pansy, and the related V. arvensis important in early studies of genetics and speciation), Rinorea (160-270), Hybanthus (90-150). World-wide; woody taxa esp. in the lowland tropics. [Photo - Leonia, Alexis fruit and flowers, Viola.]

Synonymy: Alsodeiaceae J. Agardh, Leoniaceae A. L. de Candolle

• Violaceae may be recognised by their serrate, stipulate leaves which often dry yellowish and with raised reticulum, their flowers, which are often spurred and have stamens with short filaments and very well-developed connectives that closely surround the gynoecium, and their fruit, which is often a distinctive loculicidal capsule, the rather large seeds being dispersed explosively as the fruit wall closes round them and squeezes them out. Plants are herbs, trees or lianes.

Evolution. Violaceae are the preferred hosts of the majority of fritillaries (Nymphalidae: Argynnini - see Simonsen 2006).

The largely temperate Viola is myrmecochorous (Lengyel et al. 2010), and myrmecochory as well as dispersal by larger animals and by wind also occurs in more tropical taxa.

Chemistry, Morphology, etc. For information on Fusispermum, see Cuatrecasas (1950) and Hekking (1984), the former describes the scales as being ventral appendages of the connective. Viola has storied cambium. The basic morphology and anatomy of Fusispermum will repay study given its phylogenetic position and uncertainties in the interpretation of its distinctive stamens and disc. Feng and Ballard (2005) suggested that even those Violaceae with polysymmetric adult flowers were monosymmetric earlier in development, so "flowers monosymmetric, at least in bud" may be an apomorphy for all/most of the family. In Anchietea and Decorsella the seeds mature exposed on the open carpels.

Melicytus is woody, dioecious, and baccate; the flowers are almost radially symmetrical... Not surprisingly, woody Violaceae are quite commonly often wrongly identified or not named at all, as Ron Leisner will confirm - however, the vegetative characters mentioned above do help.

For embryology, etc., see Singh (1970), for chemistry, see Hegnauer (1970, 1990), for cyclotides, see Burman et al. (2010), for general information, see Hekking (1988) and Munzinger and Ballard (2003: also key to genera, two undescribed). An unpublished thesis by Feng (2005) includes a phylogeny of the family and floral developmental details of seven genera.

Phylogeny. There is good support for the relationships [Fusispermum [Rinorea + the rest]], with the old Leonioideae being embedded within Violoideae (Tokuoka 2008, see also Feng & Ballard 2005; Ballard et al. 2009). Bakker et al. (2006b) discuss relationships in African Rinorea.

Classification. The large genus Hybanthus is polphyletic, to be cut up into nine genera, perhaps... (Ballard et al. 2009).

PASSIFLORACEAE Roussel, nom. cons.   Back to Malpighiales

Cyclopentenoid cyanogenic glycosides and/or cyclopentenyl fatty acids +, cyanogenic glycosides derived from valine and isoleucine + [?Malesherbiaceae]; (plant with unpleasant smell); (foliar glands +), colleters +; K + C together forming a tube, (corona or scales on tube), styles separate; aril +, endotestal cells large, exotegmen palisade, endotegmen persistent; endosperm persistent, oily; biparental or paternal transmission of plastids.

27/935. Tropical, esp. America and Africa, also warm temperate - 3 subfamilies below.

Turneroideae + Malesherboideae: leaves spiral; exotestal cells arranged in lines; x = 7.

1. Turneroideae Eaton

Herbaceous or woody; plant with unpleasant smell; ellagic acid 0; cortical vascular bundles [= leaf traces] common; vessel elements with simple (and scalariform) perforation plates; stomata various; leaves conduplicate, extrafloral nectaries often on petiole/base of lamina, stipules 0 (+ - e.g. Erblichia); bracteoles often large; (flowers heterostylous), (glands or corona at mouth of tube), C contorted, deliquescent, nectary near base of tube (on sepals; filaments), microsporogenesis simultaneous, G [2, 3] (half inferior), micropyle zig-zag, hypostase +, stigmas concave, often ± penicillate; K + C tube deciduous; aril +, fimbriate; seeds often with longitudinal lines of cells; n also = 5 (13).

10[list]/205: Turnera (122), Piriquetia (44). Tropical to warm temperate America and Africa (inc. Madagascar and Rodriguez I.) (map: from Wickens 1976; Heywood 2007, in part; Arbo 2008). [Photo - Flower.]

Synonymy: Piriquetaceae Martynov, Turneraceae de Candolle, nom. cons.

2. Malesherbioideae Burnett

Herbaceous or subwoody; hairs conspicuous, multiseriate, often glandular; plant with unpleasant smell; tannins?; (cork cortical); vessel elements usu. with simple perforation plates; nodes also 1:1; leaves often deeply lobed, (margins entire; stipules foliaceous or 0), colleters?; K + C tube long, (denticulate corona at the mouth of the tube), K valvate, C valvate, androgynophore +, nectary at base; G [3, 4], micropyle endostomal, large protrusion from chalazal region, styles slender, stigmas capitate-clavate, ?type; K + C tube persistent; seeds pitted, aril 0; endosperm type?

1[list]/24. Andean South America from Peru S., esp. N. Chile (map: see Gengler-Novak 2002). [Photo - Habit]

Synonymy: Malesherbiaceae D. Don, nom. cons.

3. Passifloroideae Burnett

Woody; leaves spiral, conduplicate, (margins entire), glands common on petiole or lamina; flowers (3-)5-merous, K + C tepaloid, corona of (1-)2-several rows of filaments or membranes (0), nectary ± on K/C tube, (A basally connate), anthers versatile, pollen to 12-colporate; G [(2-)3(-7)], styles separate, stigmas capitate, papillae multicellular; fruit usu. a berry; seeds often flattened, sculpted, bony, hairy or not, ruminate; testa multiplicative, sarcoexotestal or not, endotesta crystalliferous, lignified or not; n = 6 (7) 9(-12).

16[list]/705. Tropics to warm temperate, especially Africa and America - two tribes below.

3A. Passifloreae de Candolle

Plant also herbaceous climbers with simple branch tendrils; flavonols +, ellagic acid +/0, tannins 0; anomalous secondary thickening quite common; vessel elements with simple perforation plates; wood often fluorescing; supernumerary buds +; leaves spiral, (compound), conduplicate, (margins entire), 2ndary veins often palmate, glands common on petiole or on lamina surface; (plant dioecious), inflorescence cymose; (C 0), corona of (1-)2-several rows of filaments or membranes (0), nectary ± on K/C tube, (A basally connate), gynophore or androgynophore frequent, pollen to 12-colporate, funicle often long, nucellar apex pointed, micropyle bistomal or zig-zag, stigmas capitate or divided [Adenia], papillae multicellular; fruit a berry (capsule - Passiflora section Xerogona); seeds hairy or not, often sculpted, testa multiplicative, sarcoexotestal or not, endotesta crystalliferous, lignified or not; n = 6 (7) 9(-12).

10/675: Passiflora (525), Adenia (100). Tropics to warm temperate, especially Africa and America (map: from van Balgooy 1975; George 1982). [Photo - Collection]

3B. Paropsieae de Candolle

Trees or shrubs; vessel elements in multiples, with scalariform perforation plates; leaves spiral, reduced [orthotropic axes], or two-ranked [plagiotropic axes], 2ndry venation pinnate, glands especially on lamina margin and apex, (stipules 0); inflorescence racemose; (A -30; partly connate), androgynophore +/0, (pollen 6-porate), nectary 0 (annular); G [(2-)3-6], short gynophore +/0, (style single [Barteria]); seeds scrobiculate; n = ?

6/ca 22: Paropsia 12. Tropical, esp. (west), Africa (map: from Sleumer 1970; de Vos & Breteler 2009).

• Turneroideae are herbs to woody plants that may be recognised by their often very hairy, serrate, exstipulate leaves with strong secondary venation. The flowers, with their calyx and corolla together forming a tube, contorted and deliquescent yellow or sometimes red corolla, parietal placentation, and often bifid, fringed stigmas, are distinctive. The loculicidally capsular fruits have arillate seeds with a minutely and often regularly reticulate testa.

• Malesherbioideae are more or less herbaceous, foetid and often densely glandular-hairy plants with distinctive flowers. The calyx and corolla together form a long tube; the sepals and petals are both valvate. There is an androgynophore, the floral tube is persistent in fruit, and the styles are often subapical on the capsule.

• Many Passifloroideae are tendrillar vines or lianes; the leaves are alternate, stipulate, often with palmate venation, and often with glands on the lamina or petiole. The tendril is often oblique to the axis; a flower may be lateral to it, or paired flowers are borne on it or at its base. The axillary buds are superposed, and the lower bud produces the inflorescence/tendril. Floral features are, however, more important for the recognition of the family. The calyx and corolla are often similar and fused to each other at the base, and there is usually a complex corona. There is a gynophore or androgynophore, often five stamens with large and versatile anthers, and a three-carpellate gynoecium with parietal placentation. The fruit is a berry, and the often flattened seeds are arillate.

Evolution. The cyclopentenoid glycosides common in Passifloraceae may be sequestered by caterpillars feeding on the plants and perhaps used in defence and/or even as nitrogen sources; Achariaceae also have this combination of features.

Passiflora and its relatives are known for their association with Heliconius butterflies. The plants show great variation in leaf morphology, foliar glands (some of these are involved in egg mimicry - Vanderplank 2007 for references), etc. Heliconius itself is also closely associated with Psiguria (Cucurbitaceae) and relatives, and perhaps some other plants, which it pollinates, and rather unusually ). The larvae of some Acraeinae and also of brightly-coloured Notodontidae-Dioptininae moths are also often found on Passiflora (Miller 1992; Silva-Brandão et al. 2008), and at least the former are also found on Barteria. Turneroideae are the hosts of caterpillars of several genera of Nymphalidae, alternate hosts include Salicaceae, Passifloroideae, and Violaceae (Arbo 2006 and references). Details of the association between the African ant-plant Bartera fistulosa and the ant Tetraponera aethiops are given by Dejean et al. (2008).

For the considerable anatomical variation in Adenia as well as variation in life form, see Hearn (2006, 2009a); Hearn (2009b) suggested that the place of development of vascular strands and associated parenchymatous storage tissue in root and/or stem varied spatially in the plant, hence helping to generate the diversity of growth forms in the genus.

It has been suggested that there is floral mimicry between Turnera and Malvaceae in Argentina (Benitez-Vieyra et al. 2007). Heterostyly is common in Turnera, Piriqueta and some other genera of Turneroideae.

Myrmecochory occurs in Turnera (Lengyel et al. 2010).

Chemistry, Morphology, etc. Although the tubular flowers of Passifloraceae s.l. are often described as having a hypanthium, the tube is nearly always formed from calycine and corolline elements only. For the floral and extrafloral nectaries of Passifloraceae, see Krosnick et al. (2008a, b). The latter are anatomically quite different from the former (i.a. they lack nectarostomata) and the CRABS CLAW genes is not expressed in them (Krosnick et al. 2008a). For a discussion on aril development, see Kloos and Bouman (1980); although the aril is often described as funicular, they incline to call it raphal.

Flacourtiaceae - Paropsieae (Barteria, Paropsia, etc.) are to be included with Passifloroideae (Chase et al. 2002); I have characterised them separately above. Anatomically the two are rather similar, indeed, the major variation in the subfamily seems to be associated with habit - lianes versus trees (Ayensu & Stern 1964). Passiflora and immediate relatives have stem collenchyma, cymose inflorescences, and branches developing from an accessory (superposed) bud, as is common in taxa with axillary tendrils with non-basal prophyllar buds - in Passifloreae these buds may be tendril branches or flowers. Adenia is rather different from other Passifloroideae, perhaps being more like the two other subfamilies, e.g. in having a moderately developed corona and tricolporate pollen (e.g. see Feuillet & MacDougal 2006). Indeed, Adenia has a nectary often made up of separate glands, a hollow style, and its stigma lacks multicellular papillae (Bernhard 1999a, c), in addition, it may be dioecious, it lacks an androgynophore, the stamens are sometimes connate, and there is a gynophore; some species have a true hypanthium (de Wilde 1971b).

Cyanogenic glycosides in this family have a variety of precursors, both protein and non-protein amino acids (Miller et al. 2006 for references). In species of Passiflora with strongly bilobed leaves, vernation may be modified conduplicate: the blade makes a V with an inverted V at the end of each arm. The tendril is an axillary shoot and flowers can arise from prophyllar buds. Sazima and Sazima (1978) note that the bat-pollinated flowers of Passiflora mucronata become zygomorphic as the stamens move after the flowers opens; Endress and Matthews (2006a) give this as an example of monosymmetry in the family. For floral anatomy of Passiflora, see Puri (1947), for a general account of the genus, see Ulmer and MacDougal (2004), for floral development, see Krosnick et al. (2006). Hansen et al. (2006) discuss chromosome number evolution, n = 12 may be the basal number; see also de Melo and Guerra (2003).

Do the sieve tubes have non-dispersive protein bodies? Turneroideae show biparental or paternal transmission of plastids, as may Passifloroideae (Shore et al. 1994).

In Passifloreae, carpel orientation is taken from Le Maout and Decaisne (1868) and Schnizlein (1843-1870: fam. 197); for pollen, see Presting (1965) and Spirlet (1965), for chemistry, see Hegnauer (1969, 1990), for embryology, etc., see Singh (1970), for branching, see de Wilde (1971a), for general information, de Wilde (1974), for anatomy, see Harms (1893), for stipules, see Dahlgren and van Wyk (1988), and for a general account, see Feuillet and MacDougal (2006). For general information on Paropsieae, see de Vos and Breteler (2009). I am grateful to J. M. MacDougal for information.

Cronquist (1981) suggested that Malesherbioideae lack stipules. The styles are shown as being commissural by Schnizlein (1843-1870: fam. 198). General information on this subfamily is taken from Ricardo S. (1967, he suggested that the micropyle is endostomal) and Kubitzki (2006b); for chemistry, see Hegnauer (1969, 1990).

Species of both Turnera and Piriqueta have epiphyllous flowers. Some information is taken from Vijayaraghavan and Kaur (1967: embryology), Hegnauer (chemistry), González and Arbo (2005: anatomy), and Arbo (2006: general account).

Phylogeny. Turneraceae are weakly associated with Malesherbiaceae in Chase et al. (2002), the two being strongly associated with Passifloraceae. However, basic clade limits within this group may need re-evaluating, since preliminary data suggest that a paraphyletic Passifloraceae may include Turneraceae and Malesherbiaceae (A.P.G. II 2003), while Korotkova et al. (2009: three taxa from the three families) found Turnera and Passiflora to be sister taxa with 98% jacknife support.

Arbo and Espert (2009: morphological analysis, basally pectinate tree with little support) discuss the morphology and biogeography of Turnera. For relationships within Malesherbioideae, see Gengler-Novak (2002, 2003). For a phylogeny of Passiflora, see Yockteng and Nadot (2004), Krosnick and Freudenstein (2005: also morphology), and Krosnick and Freudenstein (2006). See Hearn (2006) for a phylogeny of Adenia.

Classification. Including Turneraceae and Malesherbiaceae in Passifloraceae s.l. is an optional arrangement in A.P.G. II (2003), and given the basic similarity of the three families, they were placed in one by A.P.G. III (2009). For a revision of Turnera, see Arbo (2008 and references). Passiflora includes Hollrungia and Tetrapathea (Krosnick & Freudenstein 2006); for a formal infrageneric classification, see Feuillet and Macdougal (2004).

Synonymy: Modeccaceae Horaninow, Paropsiaceae Dumortier, Smeathmanniaceae Perleb

[Lacistemataceae + Salicaceae]: flowers small; anthers ellipsoid to subglobose; endosperm copious.

LACISTEMATACEAE Martius, nom. cons.   Back to Malpighiales

Trees; plants Al accumulators; chemistry?; vessel elements with scalariform perforation plates; sieve tubes?; petiole bundle D or deeply C-shaped, also wing bundles +; leaves two-ranked, (entire); inflorescence a raceme to dense spike; P cup-like [1-6]; A 1, the thecae ± separated and even stipitate; G [2-3], median member adaxial, placentation apical, style branches short, ?stigma; ovules 1-2/carpel, funicles thick, long, ovule type?; fruit a 1(-3)-seeded capsule; testa fleshy or not; embryo (short), with foliaceous cotyledons; n = 22, chromosomes 0.9-2.3 µm long.

2[list]/14. Greater Antilles (Jamaica), Mexico southwards, not in Chile. (map: from Sleumer 1980).[Photo - Flower, Fruit]

• Lacistemataceae are woody, evergreen plants that have stipulate and usually serrate leaves. The small flowers are borne in rather dense racemes to spikes and have an inconspicuous perianth and a single anther whose two thecae are often well separated and even stipitate. The dehiscent fruit is small, with one, sometimes to three, apical seeds.

Chemistry, Morphology, etc. Chirtoiü (1918) described the flower as having 4-5 free perianth parts and an irregularly lobed disc. The presence of an aril in Lacistemataceae needs to be confirmed (see also Corner 1976). Sleumer (1980) records one for Lacistema, but a fleshy seed coat for Lozania; an aril is obvious in neither. In the latter genus there appear to be long "hairs" inside the fruit which perhaps support the dangling seed; these hairs are thick-walled but unlignified cells that may be derived from the funicle (see also Casearia, Salicaceae). However, the embryology, etc. of the family are largely unknown.

See Sleumer (1980: as Flacourtiaceae - Lacistemeae for a monograph), and Young (2007 onwards: Lacistemataceae website. Additional information from: Lozania - Riviere 270 (anatomy), Gentry et al. 22231 (fruit); Lacistema - Aymard & Delgado 6882 (fruit), Rimachi Y. 11201 (anatomy - stomata tending to anisocytic).

Phylogeny. Lacistemataceae do not cluster with the rest of Salicaceae and Kiggelariaceae (Savolainen et al. 2000a), although they are probably in this area (Chase et al. 2002; see also D. Soltis et al. 1999, 2000). Davis et al. (2005a) place them as sister to Salicaceae s.l. (61% bootstrap, 1.0 posterior probability), as do Korotkova et al. (2009: slightly higher jacknife); as might be expected, they lack salicoid teeth.

SALICACEAE Mirbel, nom. cons.   Back to Malpighiales

Evergreen (deciduous) trees; cocarcinogen, (gynocardin, ellagic acid +), tanniniferous; cork?; vessel elements with simple or scalariform perforation plates; petiole bundle arcuate or annular with wing bundles; stomata ?; leaves spiral or two-ranked (opposite), supervolute-curved or involute, (margin entire; venation palmate; glands +; stipules 0); inflorescence various; flowers (medium-sized), 3-6-merous, (hypanthium +), K (0-)3-8(-15), often valvate (connate), C 0 or = K, (basally connate; corona +), disc often with glands or lobes (the latter intrastaminal; 0); A 1 to many (fasciculate, opposite petals), anthers (extrorse), (linear); G [2-5(-13)], (to inferior), (placentation axile), styles separate or fused +; ovules straight or anatropous, outer and inner integuments 2-5 cells across, micropyle bistomal/zig-zag, parietal tissue 5-7 cells across, nucellar cap + (0), both ± resorbed, funicle short; fruit also a berry (drupe); seeds arillate; testa also multiplicative and ± fleshy but otherwise undistinguished; exotesta palisade); (embryo green); n = 9, 10-12, 19.

55[list]/1010. Pantropical, also temperate (but few in the Antipodes) to Arctic (map: (Africa incomplete) from Sleumer 1954; Meusel et al. 1975; Sleumer 1980; Hultén & Fries 1986). [Photo - Flower, Fruit.]

1. Samydeae Dumortier

Leaves often punctate or lineate, teeth theoid; hypanthium +; P 3-7, basally connate, C 0; nectary on base of P; A 3-many, initiated simultaneously; (seed squeezed from fruit, aril vascularized - Casearia); exotegmen cells laterally flattened, crystaliferous.

13/245: Casearia (180). Pantropical, especially South America.

Synonymy: Bembiciaceae R. C. Keating & Takhtajan, Prockiaceae Bertuch, Samydaceae Ventenat, nom. cons.

[Scyphostegieae + the rest]: lamina with a small vein proceeding into the tooth, where it expands, the apex of the tooth being a variously coloured spherical gland or stout hair [salicoid tooth].

2. Scyphostegieae Zmartzy

Vessels in radial multiples, with simple (and scalariform) perforations; rays mostly uniseriate; petiole bundle annular and with adaxial mass of xylem and phloem becoming adaxial inverted plate of vascular tissue; stomata paracytic; leaves distichous; plant dioecious, inflorescences terminal, paniculate, long-lived, with large, overlapping, tubular bracts [c.f. Alpinia sect. Myriocrater!], pedicels not articulated; T 3 + 3, connate; staminate flowers: nectariferous lobes opposite A; A 3, opposite inner whorl of T, connate, extrorse; pollen ?tricolpate; carpellate flowers: G [8-13], placentation basal, stigmas sessile, ray-like, with an opening in the middle; ovules with much elongated (exo-?)bistomal micropyle, outer integument 2-3 cells across, lobed, inner integument 3-4 cells across, nucellar cap persistent, funicle well developed; fruit a fleshy capsule with lignified commissural valves; seeds with aril from funicle/outer integument; endosperm slight, perisperm +, very scanty; n = 9.

1/1: Scyphostegia borneensis. Borneo, not the southern part. [Photo - Flower, Leaf, Inflorescence.]

Synonymy: Scyphostegiaceae Hutchinson, nom. cons.

3. The Rest

Benzoylated glycosides, etc. +, cyanogenic glycosides 0 (+ - Banara); (nodes 2:2 - some Azara); (plant dioecious/monoecious); (C 0; more than K - e.g. some Scolopieae); A initiation centrifugal; (pollen inaperturate - Populus); G [2-5(-13)], (inferior - Homalium); (micropyle exostomal - Idesia; endostomal - Oncoba), (outer integument lobed - Caloncoba); embryo sac elongated, ± protruding into the micropyle, (bisporic, Allium-type); (seeds with hairs [of arillate origin]), (testa vascularized, sarcotesta + - Oncoba); (endotesta palisade - Oncoba); (endosperm 0 - Salix).

41/765: Salix (450), Homalium (180), Xylosma (85), Scolopia (37), Banara (31). Worldwide, but only Saliceae cold Temperate/Arctic, few Australia, not New Zealand.

Synonymy: Flacourtiaceae Richard, Homaliaceae R. Brown, Poliothyrsidaceae Doweld

• Salicaceae can be recognised by their alternate, serrate, stipulate leaves often with distinctive "salicoid teeth"; these latter have a small vein proceeding into the tooth, where it expands, the apex of the tooth being a variously coloured spherical gland or stout hair. The flowers often have many spreading stamens and a commonly three-carpellate gynoecium with parietal placentation and either separate styles or a long, persistent style; the fruit is often a capsule. When there are both sepals and petals, the two whorls are in a regular alternating arrangement, and the nectariferous disc or nectar glands are often outside the stamens. A number of taxa have pellucid foliar glands (Abatia, Casearia, Ryania, Zuelania).

Evolution. Boucher et al. (2003) described Pseudosalix, an Eocene fossil from North America, which is morphologically intermediate between Salix and more florally conventional Salicaceae.

Salix and its immediate relatives are ectomycorrhizal.

Boeckler et al. (2011) discuss the anti-herbivore properties of the phenolic glycosides characteristic of Salix and its immediate relatives, nevertheless, a number of insects and fungi are associated with these plants and their immediate relatives. Ehrlich and Raven (1964) noted that Atella (Nymphalinae) feeds on Flacourtiaceae and Salicaceae, while some Notodontidae moths (Miller 1992); rusts (e.g. Melampsora spp. on Salix, M. idesiae on Idesia - Holm 1979), etc., show similar host patterns. Some hundreds of species of gall-forming sawflies (Hymenoptera - Tenthredinidae - Nematini) are by far the most common on Salix and Populus among their angiosperm hosts, although they have yet to be recorded from other Salicaceae s.l. (Roininen et al. 2005). Unlike other galls, sawfly-induced galls result largely from stimuli provided by the ovipositing wasp, which may inject fluids into the plant, rather than from the activities of the larvae, so the galls assume their mature forms before the eggs hatch (Redfern 2011).

There is a gene duplication in the common ancestor of Salix and Populus, the salicoid duplication, dated to 65-60 million years before present (Tuskan et al. 2006); it will be interesting to know if other Salicaceae s.l. have it.

Salix itself is notorious for the extent of interspecific hybridisation in the genus.

Chemistry, Morphology, etc. Banara is the only genus reported to have cyanogenic glycosides, but it is well embedded within Salicaceae (Chase et al. 2002). The perforation plates of the tracheary elements are more or less simple and the intervascular pits are small. Xylosma, Flacourtia, etc., have groups of large sclereids in the phloem (Zahur 1959). Xylosma and some Casearia seem to have unilacunar nodes. Leaf traces arise an internode below the leaf they innervate in Hasseltia.

Casearia can have phyllanthoid branching, the orthotropic axes having spirally arranged and reduced leaves while the plagiotropic branches are sylleptic and have fully-expanded and two-ranked leaves. Abatia has opposite leaves with at most very small stipules and marginal glands at the base of the lamina. Salicoid leaf teeth are quite variable, but all have secretory palisade cells over parenchyma and are well supplied by vascular tissue, especially xylem (Wilkinson 2007). Thadeo et al. (2008; see also Thadeo & Meira 2009) discuss the similarity between leaf teeth and foliar nectaries in Salicaceae, in particular the foliar nectaries of Prockia crucis that secrete fructose, glucose, sucrose, etc. There are also taxa with pli-nerved leaf blades and foliar glands in Salicaceae - in many ways this is a vegetatively rather heterogeneous clade.

Populus is dioecious and wind-pollinated. The valvate perianth members of Abatiaare basally connate and bear many filamentous processes, and the flowers lack a nectary. The nectary is very variable, and it is often made up of lobes; it is then sometimes intrastaminal. It has been claimed that the nectary of Salix represents a perianth whorl, but Alford et al. (2009) suggest that it is like that of other members of the family; there are ± receptacular nectaries associated with the stamens in taxa in the clade sister to [Salix + Populus]. Elongated embryo sacs occur in both Salicaceae and old Flacourtiaceae (Steyn et al. 2005a), indeed, the embryo sac more or less protrudes into the micropyle in Archevaletaia (Mahshwari 1950). Corner (1976) described the micropyle of Scyphostegia as being exostomal. Corner (1976) noted that taxa had either a more or less fibrous exotegmen (they are now mostly in Salicaceae) or a massive, non-fibrous exotegmen (taxa with this seed coat are now in Achariaceae); in both cases the exotegmen is lignified. The exotegmen of Dovyalis consists of ribbon-type cells.

Some information is taken from Hegnauer (1973, 1990, also 1966, 1989) and Chai (2009), all as Flacourtiaceae, chemistry, van Heel (1977, 1979: testa anatomy), Miller (1975: wood anatomy), Spencer and Seigler (1985: chemistry), Lemke (1988: general), Gavrilova (1998: pollen), Leskinen and Alström-Rapaport (1999: relationships of Salix and its immediate relatives), and Steyn et al. (2004, 2005a, b: ovule and seed development, summary in latter paper); see also Judd (1997a) and especially Chase et al. (2002). Bernhard and Endress (1999) discuss androecial initiation. For Scyphotstegia, see Metcalfe 1954 (anatomy); van Heel 1967 (flowers and fruits); and Hutchinson 1973 (the diversity of early interpretations of the gynoecium).

Phylogeny. It had been observed in the past that Salicaceae s. str. and Flacourtiaceae-Idesieae were very close, despite the distinctive catkins of the former - they have distinctive leaf teeth, phenolic-type compounds such as salicin are found here only, etc. (Miller 1975), and as just noted, rusts and caterpillars, perhaps keying in on chemical characters, show similar distributions (see e.g. Meeuse 1975).

Chase et al. (2002) have greatly clarified the phylogenetic situation in the old Salicaceae-Flacourtiaceae area (see also Judd 1997a; Nandi et al. 1998; T. Azuma et al. 2000; Savolainen et al. 2000a), although sampling within tribes still needs to be extended. It should be noted that Casearia, which appears to lack salicoid leaf teeth and has apetalous flowers with the disc on the basal-adaxial surface of the calyx, is sister to the rest of Salicaceae, although support for this position is weak (Chase et al. 2002, but cf. D. Soltis et al. 1999, 2000). Circumscription of groups within Salicaceae: Abatieae, Bembicieae, Prockieae (inc. Banareae), Oncobeae (Oncoba only), Homalieae, Saliceae, Samydeae (Casearieae), Scolopieae, and Scyphostegieae (see Chase et al. 2002). Tribal limits may well have to be adjusted, thus Saliceae will probably have to be expanded, Flacourtieae in their current circumscription are polyphyletic, etc. Relationships around Salix are [Microhasseltia, etc. [[Salix + Populus] [Olmediella [Bennettiodendron + Idesia]]]; characters like hairy seeds, sepals deciduous in fruit, loss of corolla, and dioecy are apomorphies at various levels within this clade (Alford et al. 2009). For a phylogeny of Salix, see T. Azuma et al. (2000) and Chen et al. (2010). Trichostephanus (Trichostephaneae) was not assigned to any family (Chase et al. 2002), but in lacking petals and in having a disc at the base of the calyx it is like Casearia (Samydeae). Oncoba is remarkably like other members of the erstwhile Oncobeae (see now Achariaceae - Lindackerieae), but they differ in chemistry, leaf tooth type, and stamen initiation; it is perhaps to be assigned to Flacourtieae.

Classification. Chase et al. (2002) provide a detailed tribal classification for the clade, which should be consulted; it is only partly adopted here pending more detailed sampling. Alford (2003) recognised three families for the New World genera previously included in Flacourtiaceae - in addition to Achariaceae, Berberidopsidaceae and Lacistemataceae. Salicaceae have dilated stigmas and petals and sometimes sepals absent, while Flacourtiaceae s. str. have attenuate, lobed, or capitate stigmas and petals present or absent.

Generic limits in the Casearia group neeed attention (Samarakoon et al. 2010).

Previous Relationships. In the Englerian system Salix was often kept with wind pollinated Amentiferae, not at all close to Flacourtiaceae, a family that was also recognised at the time and which encompassed the bulk of Salicaceae above and also Achariaceae, etc.; see Gilg's (1914) emphatic rejection of Hallier's suggestion that there might be a link between Idesia (Flacourtiaceae) and Salicaceae. Salicaceae s. str. have cuticle waxes as platelet rosettes, or 0; inflorescences catkins; P much reduced; G [2], collateral, ovules usu. unitegmic; seeds with long placental hairs at base; embryo green. These are mostly derived features.

Thanks. I am grateful to S. Zmarzty for comments.

[Lophopyxidaceae + Putranjivaceae]: stomata paracytic; style branches short or 0; fruit 1-seeded.

Evolution. This clade may have separated in the Cretaceous-Albian 111-100 million years before present, Lophopyxidaceae and Putranjivaceae themselves diverging at end Coniacian or thereabouts ca 85 million years before present (Davis et al. 2005a).

Davis et al. (2005a) found a strong association between these two families; they may in turn be associated with the group of families with parietal placentation.

LOPHOPYXIDACEAE H. Pfeiffer   Back to Malpighiales

Liane with leaf tendrils; chemistry?; branches with lateral bud at base; secondary thickening with included phloem; vessel elements with simple perforation plates; phloem stratified; nodes ?; petiole bundles arcuate; leaves spiral; plant monoecious, inflorescence branched, flowers in clusters, sessile, small, K connate basally, valvate, C very small, staminate flowers: stamens = and opposite sepals, cordate glands adnate to C; carpellate flowers: glands forming a lobed disc; G [(4) 5], opposite petals, stigmas subulate; ovules with small funicular obturator, ?integument; fruit a 5-winged samara; seed coat?; endosperm ?development, +, cotyledons long; n = ?

1/1: Lophopyxis maingayi. Malesia to the Solomon and Caroline Islands (map: from Sleumer 1971b).

• Lophopyxidaceae are tendrillate lianas with quite strongly serrate leaves that have pinnate venation; the flowers are small and are borne in tight clusters along the branched inflorescences. The one-seeded fruit has five wings.

Chemistry, Morphology, etc. Lophopyxis lacks information on everything from gross morphology to embryology. Sleumer (1971b) described the tendrils as being leaves and also bud-bearing branches; the ultimate spirally-recurved portion seems to be foliar.

Previous Relationships. Lophopyxidaceae were included in Celastraceae by Cronquist (1981) and Hutchinson (1973), in Celastrales by Takhtajan (1997), but placed close to Pandaceae (represented by Microdesmis) by Savolainen et al. (2000a; see also Chase et al. 2002).

PUTRANJIVACEAE Endlicher   Back to Malpighiales

Evergreen trees; cucurbitacins [triterpenes], glucosinolates, biflavonoyls +; cork?; vessel elements with scalariform perforation plates; petiole bundles elliptic; hairs unicellular; leaves two-ranked, (veins running into opaque deciduous teeth, or spines); plant dioecious, inflorescence fasciculate; P 4-5(-7), staminate flowers: A (2-)3-20(-many; extrorse), disc + or 0; carpellate flowers: G 1[-4(-9)], stigmas flap-like, ?type; ovules epitropous, nucellus ca 2 cells thick, disintegrating early, micropyle (exo/)endostomal, outer integument 3-9 cells and inner 6-14 cells across, (unitegmic, 6-9 cells across - D. macrostigma), endothelium +, parietal tissue ca 2 cells across, placental obturator +; megaspore mother cells 2-3; fruit a drupe; testa vascularized, exomesotesta sclereidal, tegmen ± multiplicative, 6-24 or more cells thick, exotegmic cells cuboidal; endosperm copious; n = (19) 20 (21).

3[list]/210: Drypetes (200). Tropical, esp. Africa and Malesia (map: from FloraBase 2005; Andrew Ford, pers. comm). [Photo - Flower, Fruit]

• Putranjivaceae are trees to shrubs that may be recognised by their two-ranked often rather coriaceous leaves that are asymmetrical at the base and dry a greyish color; they frequently taste peppery or like an inferior radish when fresh, although the taste may take a little time to develop (mustard oils!). The fasciculate flowers are frequently rather small and the single-seeded drupe is often crowned by the persistent, flap-like stigmas.

Evolution. Perhaps not surprisingly, caterpillars of pierid butterflies have quite often (23/2690 records) been recorded from this group (see also Brassicales and Fabaceae) - nothing so far is known about Lophopyxidaceae - and species of the Indo-Malesian Appias subgenus Catophaga (albatrosses) are found feeding more or less indiscriminately on Drypetes (Putranjivaceae) and Capparaceae (Yata et al. 2010). In Drypetes natalensis, at least, consitutively-released isothiocyanates are part of the floral odour, but exactly how they may be functioning is unclear (Johnson et al. 2009).

Chemistry, Morphology, etc. For chemistry, see Hegnauer (1966, 1989, as Euphorbiaceae), for embryology and seed anatomy, see Singh (1970), Stuppy (1996), and Tokuoka and Tobe (1999, 2001 - Lingelsheimia included, but tegmen 3-4 cells thick and testa vascularized, to be placed in Phyllanthaceae - see Kathriarachchi et al. 2005), for wood anatomy, Hayden and Brandt (1984 - it is like that of Aporusa, etc. [= Phyllanthaceae]). For a checklist and bibliography, see Govaerts et al. (2000).

Previous Relationships. Putranjivaceae have usually been included in Euphorbiaceae (as by Webster 1994, in Phyllanthoideae), but can be distinguished i.a. by their chemistry, embryology, and fruit. They are also certainly not to be placed with the rest of the glucosinolate families in Brassicales (e.g. Rodman et al. 1997, 1998).

[Ctenolophonaceae [Erythroxylaceae + Rhizophoraceae]]: leaves opposite, stipules enclosing the terminal bud, interpetiolar; pedicels articulated; nectary on outside of A; A 10, of two lengths, anthers ± basifixed, connate basally, (minute corona +); G postgenitally united, stigmas capitate/lobed, papillate; ovules 2/carpel, collateral, apical, pendulous, epitropous, nucellus laterally thin, disintegrates, endothelium +, placental obturator +; K persistent in fruit; seeds exotestal; endosperm +.

Chemistry, Morphology, etc. See Matthews and Endress (2011) for details of the floral morphology of this clade.

Phylogeny. There is weak support for an association of [Caryocaraceae [Linaceae + Irvingiaceae]] with this clade (Soltis et al. 2007a), and they have a number of features in common, such as a basally connate androecium, epitropous ovules with an endothelium, etc. (Matthews & Endress 2007). Ctenolophonaceae, etc., might also be associated, but their floral similarities did not seem to be so great. However, Wurdack and Davis (2009) found support for the clade [Ctenolophonaceae [Erythroxylaceae + Rhizophoraceae]] which in turn...???

CTENOLOPHONACEAE Exell & Mendonça   Back to Malpighiales

Woody; ellagic acid?; vessel elements with scalariform perforation plates; oxalate crystals +; cuticle waxes 0; stomata anomo- or anisocytic; hairs tufted/stellate; petiole bundle arcuate; leaves entire; inflorescence terminal, ?thyrsoid; K quincuncial, (with 1 trace), C protective in bud, contorted, caducous; nectary disc +; A adnate to base of C; pollen 3-9 stephanocolporate; G [2], septae thin, style +, branches short; ovules with zig-zag micropyle, integuments lobed, outer integument ca 5 cells across, inner integument ca 11 cells across; fruit a [?kind] capsule, K swollen; seed single, persisting on columella; arillode ± hairy, exotestal cells palisade, the outer wall thickened; endosperm copious, cotyledons very large, folded; n = ?.

1[list]/3. W. Africa, Malesia (map: from van Hooren & Nooteboom 1988b; fossils [green] from Krutzsch 1989).

• Ctenolophonaceae are trees that may be recognised by their opposite, entire leaves with interpetiolar stipules and their terminal inflorescences with rather elongated flower buds. The rounded sepals are persistent and accrescent, and the grey-drying and closely-ribbed fruit is distinctive. There is a single seed half enveloped by the hairy arillode; it remains attached to the slender central columella.

Evolution. Ctenolophonaceae may have diverged in the Cretaceous-Albian 111-100 million years before present ([109.6-]101.8[-96.6]/[97.1-]91.0[-88.1] million years before present: Davis et al. 2005a). The distinctive pollen is known as fossils from South America and India, the earliest records being from Africa in the Upper Cretaceous (Muller 1981; Krutzsch 1989).

Chemistry, Morphology, etc. Like Humiriaceae, there are "marginal" stomata on the disc and the anthers have a broad connective (Link 1992b); the wood anatomy is also similar. Takhtajan (1999) perhaps implies that there may be an endothelium, but embryology, etc., are largely unknown.

Some information is taken from van Hooren and Nooteboom (1988b).

[Erythroxylaceae + Rhizophoraceae]: tropane [hygroline] and pyrrolidine alkaloids, non-hydrolysable tannins +; sieve tube plastids with protein crystalloids; mucilage cells common; stomata paracytic; leaves involute, colleters +; inflorescence cymose; K valvate, postgenitally united, C ± clawed, conduplicate, petals enclosing a stamen/stamens; antepetalous stamens longer than antesepalous; median G adaxial, style somewhat impressed; (micropyle endostomal); fruit a septicidal capsule; seeds arillate, exotestal cells enlarged, thick-walled, ± tanniniferous; endosperm starchy, embryo green.

Evolution. This clade may have diverged in the Cretaceous-Aptian around 114 million years before present ([119.3-]113.8[-110.2]/[105.7-]101.6[-102.1] million years before present: Davis et al. 2005a).

Chemistry, Morphology, etc. Although an unexpected family pair, when comparing Aneulophus (Erythroxylaceae) with non-mangrove Rhizophoraceae, the differences are then less obvious, and the two families have several synapomorphies. For floral development, see Matthews and Endress (2007).

Previous Relationships. Rhizophoraceae used to be placed in Myrtales (Cronquist 1981) or Myrtanae (Takhtajan 1997), largely because of their vestured pits and inferior ovary, but they are well supported as sister to Erythroxylaceae (e.g. Setoguchi et al. 1999; Schwarzbach & Ricklefs 2000; Chase et al. 2002; Korotkova et al. 2009).

ERYTHROXYLACEAE Kunth, nom. cons.   Back to Malpighiales

Smallish trees and shrubs; mycorrhizae 0; ellagic acid 0; vessel elements with simple perforation plates; wood commonly with SiO₂ grains; nodes with lateral bundles originating well before the central, forming cortical bundles; sclereids +; petiole bundle arcuate to annular with medullary and adaxial bundles; branching from previous flush; buds perulate; leaves usu. two-ranked (spiral) and stipules intrapetiolar; inflorescence often fasciculate; (pedicel not articulated - Aneulophus?), heterostyly common; (hypanthium + - Nectaropetalum); K connate basally, C protective in bud, with fringed bilobed ligule (0); nectary glands on outside of A tube; A obdiplostemonous, latrorse, (connective not thickened); pollen trinucleate; G [(2-)3(-4)], (adaxial only fertile), (short), (stylar canal +), branches well developed; also 1 ovule/carpel, outer integument 2-5 cells across, inner integument (ca 3?-)5-9 cells across, parietal tissue 2-4 cells across, nucellus below embryo sac extensive, hypostase 0, 2 vascular bundles in raphe; fruit often a 1-seeded drupe, A also persistent; tegmen multiplicative or not; (endosperm 0); n = 12.

4[list]/240: Erythroxylum (230). Pantropical, esp. American (map: from van Steenis and van Balgooy 1966; Heywood 1978). [Photo - Flower, Fruit.]

• Erythroxylaceae are shrubs to trees that can be recognised by their entire leaves, stipules that are at least in part interpetiolar, and usually fasciculate inflorescence with rather small flowers; both calyx and filaments persist at the base of the fruit. Erythroxylum itself has intrapetiolar stipules, and these are especially persistent on the closely-set bud scales, there are often longitudinal markings on the leaves, the filaments are often of two different lengths and are basally connate, and the fruit is a drupe.

Cocaine is sequestered by the larvae of Eloria noyesii, a lymanitrid moth.

Chemistry, Morphology, etc. The nodes were described as being unilacunar by Sinnott (1914), however, there are lateral traces although their gaps may be inconspicuous and the traces themselves may depart from the vascular cylinder well before the central trace (Rury 1982). Erythroxylum sometimes has milky exudate. Are the lamina teeth theoid? The leaves of Erythroxylum coca were described as being revolute by Cullen (1978); they are involute (e.g. Peyritsch 1878; Weberling et al. 1980; Rury 1982; Keller 1996). Matthews and Endress (2011) described the complexity of the postgenital fusion of the petals.

Aneulophus has seeds with a thick testa, thin tegmen, and aril, opposite leaves with colleters and inter/intrapetiolar stipules, and a septicidal capsule; from petal length, it appears that the flowers are monosymmetric.

For chemistry, see Hegnauer (1966, 1989) and Aniszewski (2007), for ovule and seed, see Rao (1968) and Boesewinkel and Geenen (1980).

Synonymy: Nectaropetalaceae Exell and Mendonça

RHIZOPHORACEAE Persoon, nom. cons.   Back to Malpighiales

Trees; ellagic acid +; vessel elements with simple and/or scalariform perforation plates; true tracheids +; pits vestured; nodes also multilacunar, often with split-laterals; subepidermal laticifers in flower; cristarque cells?; branching from current flush; (leaves supervolute - mangroves), (margins entire); inflorescence axis often evident; K (3-)4-5(-16), C small, often hairy, variously lobed, fringed, or with filiform appendages, aristate; A (= or) 2X C (more), anthers ± dorsifixed, (fasciculate; free); nectary on ovary or hypanthium (0); G [2-many], opposite sepals, when 2, lateral, septae often thin/disintegrating, style + (branched - Gynotroches), stigma also ± punctate, ?type; (micropyle also zig-zag), outer integument 3-6 cells across, inner integument 4-8(-20?) cells across, (endothelium 0); parietal tissue 1-3 cells across; megaspore mother cells several, antipodals ephemeral; (endotesta crystalliferous); micropylar and chalazal endosperm haustoria + {?distribution], embryo (short), green; n = (13), 14, 16, 18, 21; germination epigeal, cotyledonary node unilacunar.

16[list]/149. Three groups below. Pantropical (map: from Ding Hou 1958; van Steenis 1963; George 1984; Tomlinson 1986; Juncosa & Tomlinson 1988a). [Photo - Flower. Flower, Fruit.]

[Macariseae + Paradrypetes]: ?

1. Macariseae

Crystals solitary; (leaves "alternate"), stipules valvate; (hypanthium +); K open; anthers latrorse; stigma not lobed; (seeds winged at micropylar end; arillate).

7/94: Cassipourea (62), Dactylopetalum (15). Tropical America and Africa, also peninsula India and Sri Lanka.

Synonymy: Cassipoureaceae J. Agardh, Legnotidaceae, nom. illeg., Macarisiaceae J. Agardh

2. Paradrypetes

Raphides +; lamina with long, zig-zag intersecondary veins; plant dioecious; flowers small; P 3-4; staminate flowers: pollen grains spiny, nectary 0; pistillate flowers: placental obturator +, style 0; fruit a drupe; seed coat vascularized; endosperm starchy, abundant, cotyledons plicate, broad.

1/2. Brasil.

[Gynotrocheae + Rhizophoreae]: stilt roots present; rootlets without root hairs; leaves bijugate, stipules imbricate; hypanthium +, ovary ± inferior; obturator 0; testa vascularized.

3. Gynotrocheae

(Stilt roots 0); (petals entire); G often more than K; ovules (to 8/carpel), tenuinucellate, outer integument 2-3 cells across, inner integument 2-4 cells across; megaspore mother cell 1); fruit a berry; exotesta mucilaginous, tanniniferous, other testal cells crystalliferous, tegmen 0, or fibrous to palisade, meso- and endotegmen persist; cotyledons short, or large, involute [Carallia, Pallacalyx].

4/30: Crossostylis (10). Indo-Malesia, Madagascar.

4. Rhizophoreae

Stomata cyclocytic; abaxial hypodermis +; sclerenchymatous sheath of midrib at most weakly developed; leaves entire; (C postgenitally united above base); (anthers locellate - Rhizophora); endothelium 0; fruit indehiscent, 1-seeded; seed coat undifferentiated, tegmen not persisting; (endosperm overflows from embryo sac); (cotyledons convolute - Rhizophora, Bruguiera); seeds germinating on tree; cotyledonary node tri- or multilacunar.

4/17: Rhizophora (?9). Pantropical, but centred on the eastern Indian Ocean (see the blue area in the map above).

Synonymy: Mangiaceae Rafinesque

• Rhizophoraceae are shrubs to trees that may be recognised by their opposite often serrate leaves and large interpetiolar stipules. The flowers are quite often other than 5-merous, the calyx is thick and valvate, the petals are often lobed or fringed, each enclosing one or small groups of stamens, and the ovary is often more or less inferior. Gynotrocheae and Rhizophoreae have aerial prop roots.

Evolution. Even though Rhizophora is known from the Caribbean more or less continuously since the late Eocene, the common ancestor of the existing populations there may have arrived in the New World some 40 million years later, only ca 11 million years before present (Graham 2006).

Mangrove taxa in Rhizophoraceae are derived within the family (e.g. Schwarzbach & Ricklefs 2000) and are most diverse in the Southeast Asia-Malesian area. Seeds of these taxa have little endosperm and are viviparous (aquatic/marine/mangrove plants quite commonly have large embryos), and in all genera except Bruguiera the endosperm overflows from the seed, pushing open the micropyle as it does so. After the seed falls from the tree it may float in the water, the hypocotyl straightening and establishment of the seeding being by the development of lateral roots (Juncosa & Tomlinson 1988b). Depending on the genus, there are either stilt roots or pneumatophores, and axillary buds soon die so the plants cannot regenerate when cut (or if the twigs are killed by frost), etc. (see Tomlinson 1986 for much useful information). Robert et al. (2009) discuss the hydraulic architecture of the wood of Rhizophora.

For the evolution of the mangrove ecosystem, which also involves diversification of clades of molluscs, etc. (Reid et al. 2008), see Ellison et al. (1999) and especially Plaziat et al. (2001 and references). Nypa (Arecaceae), today found glowing along rivers to the upper limits of tidal influence, appeared in the Upper Cretaceous ca 70 million years ago and by the early Palaeocene ca 55 million years ago was found in both the Old and New Worlds. By the Eocene, 50 million years ago, many mangrove genera are known from the fossil record, and several, including Pelliciera, are known from both the Old and New Worlds (but see Martínez-Millán 2010). Fossil hypocotyls identified as Ceriops and preserved with good anatomical detail are known from the Lower Eocene London Clay (Wilkinson 1981), although Collinson and van Bergen (2004) noted that the distinctive curvature of modern mangrove (Rhizophoreae) seedlings had not been found in these fossils. The mangrove habitat includes relatively few species of flowering plants, and apart from Rhizophoraceae largely unrelated species make up the bulk of the mangrove vegetation. Families represented include Primulaceae-Myrsinoideae (Aegiceras), Lythraceae (Sonneratia), Acanthaceae (Acanthus ilicifolius, Avicennia), Tetrameristaceae (Pelliceria), Malvaceae (Hibiscus tiliaceus - this species also grows on seashores), etc. Interestingly, there may be considerable genetic differentiation within the Atlantic populations of mangrove species found there (Takayama et al. 2008a, b). The division of mangroves into two largely exclusive areas, the more diverse Indo-WestPacific and the Caribbean-West Atlantic areas, seems to have occurred by ca 20 million years before present (Plaziat et al. 2001). Fossil and current distributions thus seem to have little to do with each other, and the history of individual mangrove species is complicated. Thus Nypa is now Indo-Malesian, although it used to be world-wide in distribution in suitable climates and habitats, Pelliciera is Central American, although growing in Europe in the past (Plaziat et al. 2001). Even though Rhizophora is known from the Caribbean more or less continuously since the late Eocene, the common ancestor of the existing populations there may have arrived in the New World some 40 million years later, only ca 11 million years before present (Graham 2006).

Pollen in Rhizophoreae is deposited on to the hairy petals, so there may be secondary pollen presentation, but pollination is basically explosive, the stamens being held in groups by the petals until the flower is tripped by the pollinator. These petals often have an arista or other appendages, and are shaped like a tiny bivalve mollusc (Endress & Matthews 2006b). The pollen grains are very small, and in Rhizophora in particular pollination may be by wind (Juncosa & Tomlinson 1988b).

Chemistry, Morphology, etc. Growth in a number of Rhizophoraceae may be continuous, although growth patterns in Macarisieae are unknown. Cork initation in the root may be superficial for at least some taxa, perhaps just those with stilt roots (see von Guttenberg 1968 for Carallia). The leaf teeth are theoid.

There is considerable variation in merosity in the family, Carallia having K5 C5 A5 G5, but both garpel and stamen number vary (Matthews & Endress 2011). The stamens in polystemonous flowers arise from ring primordia (Ronse de Craene & Smeta 1992b). Rhizophora has transversely arranged carpels (Eichler 1876).

See also Juncosa and Tomlinson (1988: general), Tobe and Raven (1987d, 1988b: seed coat anatomy), Endress and Matthews (2006b: petal morphology) and Baranova and Jeffrey (2006: leaf anatomy); for information on Paradrypetes, see Levin (1986, 1992) and Radcliffe Smith (2001 - as Euphorbiaceae).

Phylogeny. Schwarzbach and Ricklefs (2000) found strong phylogenetic structure in the family, with three major clades. Molecular data also place Paradrypetes (ex Euphorbiaceae) here (e.g. Davis et al. 2005a), strongly supported as sister to Cassipourea (Wurdack & Davies 2008: only one species from each tribe included). Paradrypetes has a rather unexpected combination of characters (see above). At least some Macarisieae have stamens of two lengths and well-developed anther connectives (D. Kenfack, pers. comm.), probably plesiomorphic features. Crossostylis, with dehiscent fruits and arillate seeds, is embedded in Gynotrocheae, which otherwise have fleshy, indehiscent fruits and seeds without arils. Fleshy indehiscent fruits may have evolved in parallel within Gynotrocheae, or the arillate seed, etc., of Gynotroches is a reversal. Indeed, variation in testal morphology in this tribe is considerable, Gynotroches and Pellacalyx, with strongly exotegmic sseds, differing so much from Carallia, which lacks an exotegmen, that Corner (1976) prefered to segregate the former at Legnotidaceae - a comprehensive survey of seed anatomy in the family is desirable.

Classification. Schwarzbach and Ricklefs (2000) suggested that three tribes be recognized for the three major clades that were apparent in their phylogeny of the family.

Previous Relationships. Rhizophoraceae have often been associated with Myrtales (e.g. Cronquist 1981; Takhtajan 1997), and they have sometimes included or been closely associated with (Takhtajan 1997) Anisophylleaceae, here in Cucurbitales.

LINACEAE Perleb, nom. cons.   Back to Malpighiales

Cork?; vessel elements with simple or scalariform perforation plates; true tracheids +; petiole bundle(s) arcuate; cristarque cells + [rare in Linoideae]; epidermal wax crystals as parallel platelets; branching from previous innovation; leaves usu. involute, tooth ?type, petiole short; pedicels articulated; (flowers distylous); K quincuncial, C contorted, caducous; nectary +; A basally connate, pollen starchy; G [2-5], opposite petals, or median member adaxial, style more or less divided, stigmas capitate; ovule (1/carpel), endostomal, parietal tissue 4-6 cells across [which subfam.?], antipodal cells degenerate; (megaspore mother cells several); fruit often septicidal, K persistent; tegmen strongly multiplicative; endosperm variable, chalazal haustorium +, (embryo slightly curved).

10-12[list]/300 - two groups below. World-wide.

1. Linoideae

Herbs (shrubs); ellagic acid 0; vessel elements with simple perforation plates; rays uniseriate; nodes 1:1 [Linum]; cuticle waxes as parallel platelets; leaves opposite or spiral, margins entire or toothed (stipules 0); K ± equal, C clawed; nectary outside filaments or at base of C; A 5, opposite sepals, alternating with staminodes; pollen trinucleate, ?often starchy, 3-pantocolpate or pantocolporate, or inaperturate; G loculi usu. divided, stigma wet or dry; ovules tenuinucellate, (micropyle bistomal), outer integument 2(-3) cells across, inner integument 3-12 cells across, endothelium +, obturator +, with trachomes; (2-seeded mericarps also splitting along false septae, units opening adaxially); seeds often mucilaginous, exotesta with outer walls massively thickened, cross cells beneath exotegmen, endosperm scanty, (helobial), chalazal endosperm haustoria +, embryo green [Linum]; n = 6, (8), 9, (11-18, etc.).

6/240: Linum (180). Worldwide, but esp. N. temperate and subtropical (map: from Hultén & Fries 1986; Diderichsen & Richards 2003; McDill et al. 2009 - East Asia?). [Photo - Flower]

2. Hugonioideae

Woody, often lianes with branch grapnels; ellagic acid?; vessel elements with scalariform perforation plates; sclereids +; stomata accessory cells usu. lignified, lobed beneath the guard cells; branching from previous flush; leaves spiral or two-ranked, margins toothed, (stipules pectinate); (flowers tristylous); K often unequal, C at most slightly clawed, often yellow; disc at base of filaments; A 10, of two lengths; micropyle endostomal [Roucheria], outer integument 2-3 cells thick, inner integument 3-5 cells thick, hypostase +; fruit a drupe or with mericarps; seed with an at most slight arillode, testa multiplicative, mesotesta with sclerotic cells, endotesta lignified, exotegmen barely lignified or tegmen obliterated; endosperm copious to scanty; cotyledons large; n = 6, 12, 13.

4-6/61. Pantropical (map: from van Hooren & Nooteboom 1984a; Jardim 1999; McDill et al. 2009). [Photo - Flower]

Synonymy: Hugoniaceae Arnott

• The leaf may have longitudinal lines on the abaxial surface, the caducous petals are contorted and often yellow, and the fruits are often septicidal and have only a few seeds. I find Linaceae difficult to identify...

Evolution. Linaceae may have diverged in the Cretaceous-Albian 111-100 million years before present (Davis et al. 2005a).

Heterostylous flowers are scattered in Linoideae, but whether they are an apomorphy for it is unclear; breeding systems have certainly been labile (McDill et al. 2008, 2009).

Economic Importance. Seeds of flax (Linum usitatissimum) have been usedfor oil, etc., for about 10,000 years (Vaisey-Genser & Morris 2003).

Chemistry, Morphology, etc. Ellagic acid is not reported from Linoideae, but members of this subfamily are largely herbaceous. Flat vernation is reported from Linum narbonense by Cullen (1978), other taxa may be conduplicate. Bracts and bracteoles have a single trace. Tirpitzia bilocularis has a corolla tube over 2 cm long. Anisadenia, with its spicate inflorescence, stamens opposite the petals, and 2-carpellate gynoecium, each carpel having but a single seed, is very distinctive (Brummitt 2007). Tobe and Raven (2011) suggest that the inner integument is multiplicative. In Hugonioideae, only half of the ovules may develop and produce seeds. Note that septicidal dehiscence, presumably liberating pyrenes, may occur in this subfamily (Spichiger et al. 2002).

For information on the family and its possible segregates see Hegnauer (1966, 1989: chemistry), Boesewinkel (1980), Narayana (1970) and Narayana and Rao (1966, 1969, 1978a), all embryology, floral anatomy, etc., Robertson (1971: Linoideae), van Hooren and Nooteboom (1984, 1988a, b: general), van Welzen and Baas (1984: anatomy), Thompson et al. (1996: heterostyly), Jardim (1999: New World Hugonioideae) and Schmidt et al. (2010: lignans, in most Linum alone).

Phylogeny. McDill et al. (2009: focus on Linoideae) oulined phylogenetic relationships in the family; Linoideae may be monophyletic, but support is from posterior probabilities only; the status of Hugonioideae is unclear.

Previous relationships. Linaceae are weakly associated with Picrodendraceae in Chase et al. (2002a), and with Irvingiaceae in Tokuoka and Tobe (2006).

IRVINGIACEAE Exell & Mendonça   Back to Malpighiales

Trees; ellagic acid +; vessel elements with simple perforation plates; nodes ?; petiole bundle annular; cristarque cells widespread; (sclereids +); mucilage cells in epidermis and ducts elsewhere in leaf; stomata paracytic; branching from previous flush; leaves two-ranked, revolute, margins entire, 2ndary veins strong, rather close and subparallel, tertiary veins also ± parallel and at right angles to the secondary veins, stipules large, intrapetiolar and encircling terminal bud; inflorescences axillary or terminal panicles; pedicels basally articulated; flowers small, A (9) 10, filaments folded in bud, disc massive; G [2, 5], G median (when 2) or opposite sepals, 1 pendulous ovule/carpel, placental obturator +, style +, stigma punctiform, ?type; fruit a drupe [stones 1 or 5 1-seeded, or 5-seeded] or samara; testa thick, much sclerotised; endosperm slight to copious; cotyledons large, cordate; n = ?

3 (Klainedoxa, Desbordesia, Irvingia)[list]/10. Africa; South East Asia to W. Malesia (map: from Harris 1996). [Photo - Fruit]

• In Irvingiaceae, the leaves, with their longitudinal markings, their large, deciduous, intrapetiolar stipules that enclose the prominent, pointed terminal bud, and their rather closely parallel secondary venation, are distinctive. The axillary buds are also prominent, and prophylls are basal on the shoots. The pedicels are articulated at the junction with the axis; the thin calyx persists on the fruit and is conspicuously reflexed, and the disc is very obvious. The drupes often have radial fibres.

Evolution. Irvingiaceae may have diverged in the Cretaceous-Albian some 111-100 million years before present (Davis et al. 2005a).

Chemistry, Morphology, etc. Keller (1996) suggests that the leaves are involute in bud. Information is taken from Jadin (1901: anatomy), Noteboom (1967: chemistry), Harris (1996; monograph), Link (1992c), and Boesewinkel (1994: see tegmen!); details of floral orientation are taken from Eckert (1966).

Previous Relationships. Irvingia is included in Simaroubaceae-Sapindales by Cronquisy (1981) while Irvingiaceae are included in Rutales by Takhtajan (1997). Irvingia is sister to Erythroxylum in a tree presented by Fernando et al. (1995), and the stipules of Irvingiaceae, Erthroxylaceae and Ixonanthaceae are similar (Weberling et al. 1980); Irvingiaceae are weakly associated with Putranjivaceae in Chase et al (2002a) and with Linaceae in Davis et al. (2005a).

IXONANTHACEAE Miquel, nom. cons.   Back to Malpighiales

Woody; ellagic acid +; vessel elements with simple perforation plates; mucilage cells +; cuticle waxes as variously arranged platelets; stomata paracytic; petiole bundle arcuate; branching from previous flush; leaves spiral, involute, (margins entire), (stipules cauline); inflorescences axillary, corymbose; K usu. basally connate, C contorted or imbricate; A 5[opposite sepals]-20, folded in bud, pollen with supratectal spines, free disc nectaries +; G [(2-)5], (carpels subdivided), (1- Allantospermum)-2 pendulous apical ovules/carpel, placental obturator, endothelium, hypostase +, micropyle bistomal, style undivided, slender, stigma capitate or discoid; fruit a septicidal (and loculicidal) capsule opening adaxially as well, columella persistent or not, K and C persistent; seeds basally winged, or aril arising between the hilum and micropyle; endotegmen with sinuous anticlinal walls; cotyledons large; n = ?

4-5[list]/21. Pantropical (map: from Aubréville 1974; Kool 1988).

Evolution. Ixonanthaceae may have diverged in the Cretaceous-Albian 111-100 million years before present (Davis et al. 2005a).

Chemistry, Morphology, etc. The stamens opposite the petals in Ixonanthes are paired, but arise from a single trace (Narayana & Rao 1966). Narayana (1970) depicts a tegmen ca 4 cells thick, the innermost layer of which is an endothelium. See also Nooteboom (1967: chemistry), Forman (1965: general), Narayana (1970: embryology, etc.), and Kool (1980: revision of Ixonanthes, 1988: general) for information.

Previous Relationships. Robson and Airy Shaw (1962) drew attention to the "spiral convolution of the filaments and style" of Cyrillopsis which, they thought, were points of similarity between this genus and Irvingiaceae sensu stricto. However, Allantospermum and some species of Ochthocosmus also have flowers very similar to those of Cyrillopsis, with the thin calyx reflexed after anthesis (Phyllocosmus, Ixonanthes), while other species of Ochthocosmus have persistent, erect, almost scarious-looking sepals, as is common in Linaceae. Takhtajan (1997) included Allantospermum in Irvingiaceae - both have flowers with two carpels and seeds with copious endosperm, and the inflorescences of some Ixonanthaceae are indeed very like those of Irvingiaceae. On the other hand, Bove (1997) suggested that Ixonanthaceae and Humiriaceae were sister taxa, both having ellagic acid, a "free" disc encircling the ovary, and an entire stigma. In the context of Linales (Linaceae and their immediate relatives), Ixonanthaceae were distinct in their free stamens, semi-inferior ovaries and pollen grains with supratectal spines. Davis et al. (2005a) found a week association between Ixonanthaceae and the Clusiaceae group, and Tokuoka and Tobe (2006) a weak association between Ixonanthaceae and Ochnaceae.

HUMIRIACEAE Jussieu, nom. cons.   Back to Malpighiales

Trees; ellagic acid +; cork subepidermal; vessel elements with scalariform perforation plates [apo]; true tracheids +; vestured pits +; sieve element plastids with protein crystals and starch; nodes ?; sieve tube plastids with protein crystalloids and starch; mucilage cells frequent; stomata various; branching from previous flush; leaves often two-ranked, involute, tooth ?type, (margins entire), petiole short, stipules small or 0; inflorescence cymose; K connate, at least at base, (C quincuncial/cochlear); A 10-many, filaments ± connate at least basally, forming a tube, anther sacs usu. 2, separated, superposed, connective broad, prolonged; pollen exine usu. microreticulate; disc variable, from base of filaments to base of G; G [5< [apo] (4-7)], usu. opposite sepals, 1 (2) pendulous ovules/loculus, micropyle exo(endo)stomal, style undivided, stigma slightly lobed, ?type; fruit a drupe, operculate, 1- or 2-seeded, surface sculpted; exotestal cells thick-walled, lignified, tegmen multiplicative [ca 5 cells thick], cross layer beneath exotegmen; endosperm copious, perisperm slight, embryo somewhat curved; n = 12.

8[list]/50: Vantanea (16), Humiriastrum (12). Tropical America, W. Africa (Saccoglottis, also American) (map: from Thorne 1973). [Photo - Flower, Fruit.]

• Humiriaceae are evergreen trees that may be recognised by their blackish-drying, short-petiolate, toothed leaves which elongate while still rolled up and often have longitudinal lines down the blade; the buds on growing shoots are long-pointed. The young twigs are angled. The cymose inflorescences have rather small flowers with broadly rounded sepals and the anthers have conspicuously prolonged connectives. The fruit is a drupe and has a ridged or variously ornamented, operculate stone that often has cavities containing almost resin-like material.

Evolution. Humiriaceae may have diverged from other Malpighiales in the Cretaceous-Albian 111-100 million years before present ([117.2-]112.2[-108.9]/[102.8-]101.6[-100.3] million years before present: Davis et al. 2005a). Herreta et al. (2010) reject all fossils placed in this family other than some from South America, suggesting that the family originated there.

The fruits are dispersed by bats or by water, the empty cavities affording bouyancy.

Chemistry, Morphology, etc. There is no endothelium. Some information is taken from Boesewinkel (1985a: ovule and seed), Bove and Melhem (2000: pollen), and Herrera et al. (2010: general).

Phylogeny. Within Humiriaceae, Vantanea is sister to the other genera; it has three or more staminal whorls (Bove 1997). Herrera et al. (2010: more detailed morphological analysis of 40 characters) suggested that Vantanea and Humiria were successively sister to the remainder of the family, although support for this topology was weak; the [Humiria + the rest] clade had quincuncial corollas and unilocular anthers.

Previous Relationships. Bove (1997) suggested that Ixonanthaceae were sister to Humiriaceae, both having ellagic acid, a "free" nectariferous disc encircling the ovary, and an undivided style with an entire stigma.

PANDACEAE Engler & Gilg, nom. cons.   Back to Malpighiales

Trees to shrubs; cork?; vessel elements with scalariform (and simple - Galearia) perforation plates; rays 5-9 cells wide; sieve tubes with non-dispersive protein bodies; cristarque cells +; petiole bundles arcuate; cuticle waxes 0; leaves spiral and reduced on orthotropic axes, two-ranked on plagiotropic axes, involute, a single vein running into the opaque persistent tooth apex; inflorescences various, plant dioecious, flowers small, K connate or free, C valvate or imbricate, nectary 0, staminate flowers: stamens = and opposite sepals, 10, or 15, in one or two series, basifixed, connective produced or not, pistillode +; carpellate flowers: staminodes 0; G [2-5], 1 pendulous epitropous ovule/carpel, micropyle endostomal, both integuments 3-5 cells across, style +, (branched), stigmas not expanded (bilobed); fruit a drupe, surface often irregular; exotesta and endotegmen tanniniferous, exotegmen tracheoidal; endosperm ?development, +, cotyledons thin and flat, oily; n = 15.

3[list]/15: Microdesmis (10). Tropics, Africa to New Guinea (map: approximate).

• Pandaceae are evergreen trees with stipulate leaves and often very strongly plagiotropic branches that have even been confused with compound leaves. The flowers are small and inconspicuous, the plants are dioecious, and the fruit is a drupe. [Photo - Habit, Fruit].

Pandaceae seem to be a very old and isolated clade, dating back perhaps to the late Aptian (Cretaceous) 114-112 million years before present ([118.7-]113.8[-110.2]/[105.5-]101.6[-101.9] million years before present: Davis et al. 2005a).

Chemistry, Morphology, etc. Panda has straight ovules; Microdesmis has punctate leaves. The plagiotropic branches have been confused with compound leaves, especially in the derived Galearia and Panda; the stipules may be asymmetrically placed, as in Panda.

For information, mostly as Euphorbiaceae, see Forman (1966: general), Vaughan and Rest (1969), Hegnauer (1969: chemistry), Stuppy (1996: seed anatomy), Nowicke et al. (1998: pollen), Radcliffe-Smith (2001: generic descriptions) and Tokuoka and Tobe (2003: ovules and seeds). For a checklist and bibliography, see Govaerts et al. (2000, vol. 4).

Previous Relationships. Pandaceae are still often included in Euphorbiaceae, e.g. Govaerts et al. (2000) and Radcliffe-Smith (2001), but they differ from even the uniovulate taxa (Euphorbiaceae str.) in several respects, including their indehiscent fruits. Rays of Euphorbiaceae are only 1-5 cells wide (Hayden & Hayden 2000); Pandaceae lack obturators, while Euphorbiaceae have them - another difference. Dicoelia (Euphorbiaceae - Dicoelieae) and Galearia both have stamens in depressions in the petals. Dicoelia has a low, thin-walled testa, a massive exotegmen, and a moderately thickened mesotegmen (Stuppy 1996), however, it is to be placed in Phyllanthaceae (Kathriarachchi et al. 2005). Centroplacus is also not included, although it is placed sister to Pandaceae, but without much support, by Wurdack et al. (2004); see Centroplacaceae here.

OCHNACEAE Candolle, nom. cons.   Back to Malpighiales

OCHNACEAE Candolle, nom. cons.   Back to Malpighiales

Pits vestured; mucilage cellls/canals +; branching from previous flush; leaves with secondary and tertiary venation well developed; pedicels articulated; A 12< [some staminodial]; K persistent in fruit.

27/495 - five groups below. Tropical, esp. Brasil.

1. Ochnoideae Burnett

Biflavonyls, isoflavonoids +; stem with cortical (and medullary) bundles; (vessel elements with scalariform perforations); nodes also multilacunar; petiole bundle annular, (several, arcuate); stomata also paracytic; leaves with 2ndary veins strong and close, and/or with parallel tertiary veins, stipules fimbriate or not; flowers (3-)5(-10)-merous; K almost scarious; A (5-many), (development centrifugal), anthers (locellate), dehiscing by pores (not); G [(1-)5(-15)], opposite sepals, when 3 median member adaxial, placentation parietal, style long (short), stigma punctate or slightly lobed (± divided); ovules 1-many/carpel, endothelium +, micropyle endostomal; antipodals persistent; seeds winged; endotesta with small crystalliferous cells; endosperm slight, (embryo curved).

27[list]/495. Tropical, esp. Brasil (map: see Kanis 1971).

1A. Luxembergieae Horaninow

Androecium obliquely zygomorphic in bud, only adaxial A developing, filaments ± connate, anthers connate or not, pollen exine with small perforations; G [3]; n = ?

2/22. Venezuela and Brasil.

Synonymy: Luxemburgiaceae van Tieghem

Ochneae + Sauvagesieae: staminodes separate, forming a lobed disc or corolla-like tube, or 0; pollen with striate-rugulate exine.

1B. Ochneae Bartling

Vessel/parenchyma pitting not unilaterally compound; (petiole with inverted medullary bundle and subepidermal fibres); leaves two ranked, (stipules semi-intrapetiolar - Ouratea); C contorted (inner edge of petal enveloping stamens in pairs); A ob/diplostemonous to many, development centripetal, filaments long to short, (anthers dehiscing by slits); (pollen 3-celled); G [2-]5[-15], (short gynophore +), style (gynobasic, receptacle expanded), hollow or not; ovule one/locule, apotropous, integument single [= 2 fused, except sometimes at tip], 7-17 cells across, or micropyle bi- or endostomal, outer integument 3-4 cells across, inner integument 2-3 cells across [Ochna], hypostase +(/0?); antipodals enlarged; fruit indehiscent, usu. drupaceous; A persistent; testa with vascular bundles, lacking layer of small crystalliferous cells, fibrous exotegmen 0; endosperm 0; cotyledons massive, variously arranged, (unequal); n = 12-14.

9/390: Ouratea (inc. Gomphia: 200), Ochna (paraphyletic?: 85), Campylospermum (65). Tropical, especially Brazil. [Photo - Flower, Flower, Fruit.]

Synonymy: Gomphiaceae Schnizlein, Lophiraceae Loudon

1C. Sauvagesieae de Candolle

(Herbs); leaves spiral, conduplicate-flat (compound - Rhytidanthera); (flowers monosymmetric, monosymmetry developing late, involving A and G); (K with outer members smaller than the rest); (pollen exine with small perforations); G [2, 3, 5], when 3, median member adaxial; outer integument ca 2 cells across, inner integument ?3-4 cells across; seeds winged or not; exotesta with large cells, ± detached, entotesta with crystalliferous cells; endosperm with aleurone; n = 18.

16/82: Sauvagesia (40). Pantropical, only 2 spp. in Africa, most genera South American.

Synonymy: Euthemidaceae van Tieghem, Sauvagesiaceae Dumortier, Wallaceaceae van Tieghem

Medusagyne + Quiinoideae: styluli separate, ovary roof well-developed, stigma expanded; ovules often 2/carpel.

2. Medusagyne

Bud perulate; plant tanniniferous; plant glabrous; phloem stratified; true tracheids +; nodes 5:5 + 2 phloic bundles; cristarque cells 0; petiole bundles many, arcuate, variously oriented; hypodermal mucilage cells +; cuticle waxes 0; leaves opposite, venation very reticulate, stipules 0, colleters +; inflorescence terminal, ?cymose, plant andromonoecious; K basally connate; A spiral, from 5 trunk bundles, anthers basifixed, pollen porate; G [16-25], adnate to central axis, stigmas capitate, ?type; ovules 2-5/carpel, outer and inner integuments 3-4 cells across, funicles long; fruit a ribbed verrucose septicidal capsule, carpels pulling away acropetally and opening adaxially, columella persistent; seeds winged; exotesta slightly thickened; endosperm ?development, thin; n = ?

1[list]/1: Medusagyne oppositifolia. Seychelles, very rare.

Synonmy: Medusagynaceae Engler & Gilg, nom. cons.

3. Quiinoideae Luersson

Trees (lianes); mycorrhizae 0; cork?; (vessel elements with scalariform perforation plates); true tracheids +; petiole bundle annular, often complex; stomata anisocytic; leaves opposite, simple (compound; entire), 2ndary venation strong, close, tertiary venation paxillate, stipules pubescent, also interpetiolar, large, ± persistent; (plant androdioecious); K 4-5, pubescent, C 4-5(-8), usu. imbricate; A basally connate or not (adnate to the base of the C), thecae distinct, pollen exine with small perforations; G 3 [2-13], stigmas obliquely expanded, type?; ovules 2/carpel, basal; fruit a berry (follicle), striate when dry, exocarp with lacunae; seeds 1-4, usu. hairy; coat ?; endosperm development?, 0; n = ?

4[list]/55: Quiina (25), Lacunaria (12). Tropical America (map: from Schneider et al. 2002). [Photo - Flower, Fruit.]

Synonymy: Quiinaceae Engler, nom. cons.

• Ochnaceae are evergreen trees whose leaves are usually serrate, stipulate and have dense and prominent venation.

• Ochnoideae are recognisable by their alternate, often coriaceous leaves with rather sharply serrate margins, more or less brochidodromous venation - the secondary veins can be very closely parallel - and rather scaly stipules that have strong, parallel veins and also may have fringed margins. The rather scarious calyx is also distinctive, the anthers often open by pores and the style is sometimes gynobasic.

• Medusagyne has a distinctive fibrous bark rather like that of Juniperus. Its leaves are opposite, toothed, and with very strongly reticulate venation. The flowers, with their contorted petals, numerous stamens and carpels with marginal styles are distinctive, as are the fruit, the valves of which pull away from the central columella, except at their apices.

• Quiinoideae may be readily recognised, even when sterile, by their opposite or whorled, sometimes compound or deeply lobed (especially in seedlings), strongly stipulate leaves with toothed margins; the secondary veins are well-developed, the fine venation is like the strokes of a paint brush, and the stipules are more or less persistent. There are well-developed mucilaginous canals. Both stipules and sepals are pubescent and the often baccate fruits are striate when dry.

Evolution. This clade may have diverged in the Cretaceous-Albian (117-)111(-106()/(104-)99.6(-98.8) million years before present: Davis et al. 2005a). The restriction of Medusagyne to the Seychelles is noreworthy - the earliest ocean crust separating India and the Seychelles is ca 63.4 million years old (Collier et al. 2008).

Chemistry, Morphology, etc.Medusagyne and Quiinoideae are largely unknown embryologically, etc.

Sauvagesia lacks vestured pits; two other genera in Ochnoideae are recorded as having them (Jansen et al. 2001). Godoya has stratified phloem. There are mucilage cells or mucilage channels, and the plants sometimes have watery juice.

There is considerable variation in floral morphology in Ochnaceae-Ochnoideae. Sauvagesia has numerous linear staminodes, five petaloid staminodes opposite the corolla, and five stamens opposite the calyx. The antesepalous primordia of Ochna (Ochnoideae-Ochneae) show centripetal androecial development (Pauzé & Sattler 1978), while the androecia of members of the other two tribes have centrifugal development (Amaral & Bittrich 1998). Zygomorphy is largely the result of the unequal later development of the androecium, but in Philacra and Luxembergia it is evident early in development (Amaral & Bittrich 1998). Although the anthers are often porose, there is still an endothecium (quite often absent in such situations), and this perhaps facilitates reversal from the porose condition (Amaral & Bittrich 2004).

There is considerable variation in the ovule, etc., of Ochna, alternatively, some reports must be incorrect. Chikkannaiah and Mahalingappa (1974) suggest that there is no endothelium, but the nucellar epidermis seems to take over that function.

Lophira has unequally accrescent sepals, two members forming wings (there are only two carpels, each with many ovules, and the testa is thin), Batygina et al. (1991, p. 222) show Sauvagesia erecta as having a much enlarged endotesta with thick walls.

For further information on Ochnoideae, see van Tieghem (1902: general, esp. embryo), Narayana (1975) and Guèdès and Sastre (1981), both embryology, Dickison (1981: anatomy), Amaral (1991: general), and Hegnauer (1966, 1989: chemistry); for some general information, see Matthews et al. (2011).

In Medusagyne the upper ovules are ascending and epitropous, the lower ovules descending and apotropous (Batygina et al. 1991; Doweld 1998b). Additional information on Medusagyne is taken from Robinson et al. (1989: morphology), Dickison (1990a, 1990b: morphology and anatomy), and Fay et al. (1997a: relationships and morphology). For comparison of the fruit dehiscence of Medusagyne with that of some Ochnaceae, particularly some Sauvagesioideae, see Fay et al. (1997a); the anatomy of the fruits is similar to that of Caryocaraceae (Dickison 1990a).

The venation of the leaves of Quiinoideae is very distinctive, although clearly not that dissimilar from that of other Ochnaceae, and it has been studied in detail by Foster (1952 and references). Veinlets ending free in the mesophyll can be few or even absent. The stomata are described as being paracytic by Schneider et al. (2002).

Phylogeny. There is good molecular support for a monophyletic Ochnaceae s.l., e.g. Fay et al. (1997a), Nandi et al. (1998), Savolainen et al. (2000a), Chase et al. (2002) and Korotkova et al. (2009). However, relationships between the three clades are unclear, as are those of the family itself: perhaps Ochnaceae are close to Clusiaceae et al., the two families having a generally similar flavonoid spectrum (Hegnauer 1990). In both Quiinoideae and Medusagynaceae some of the ovules in each carpel abort. Froesia is sister to the rest of Quiinoideae (Schneider et al. 2006, see also 2002 for a morphological phylogeny); it has separate carpels, follicles, and glabrous seeds. Relationships among the other three genera are unclear.

Classification. Including Ochnaceae, Medusagynaceae and Quiinaceae in Ochnaceae s.l. is an optional arrangement in A.P.G. II, and they have much in common; Ochnaceae s.l. are recognized in A.P.G. III (2009).

Previous relationships. Diegodendraceae, included in Ochnaceae by Cronquist (1981), are placed in Malvales (see also Amaral 1991). Comments on the species cover of Medusagyne at the Royal Botanical Gardens, Kew, ca 1985: "cf. Actinidia. - Would be much better placed in Guttiferae or Hypericaceae - !!!!! - this plant allied to Myrtales. - Nonsense! - oh yes it is!". Hardly surprisingly, Medusagyne was included in a monotypic Medusagynales (Theanae) by Takhtajan (1997) and generally associated with Theales (e.g. Cronquist 1981); the latter was such an heterogeneous group that the further inclusion of practically anything made little difference to its description... Van Tieghem (1902) thought that on balance Clusiaceae s.l. and Ochnaceae might be close, largely because of the polystemony of the former and also some of the latter.

[Clusiaceae + Bonnetiaceae] [Calophyllaceae [Hypericaceae + Podostemaceae]]: flavones, flavonols, biflavonoids, (ellagic acid) +; xanthones common; vessel elements with simple perforation plates; schizogenous cavities +; nodes 1:1; stomata paracytic; leaves with colleters, margins entire, stipules 0; inflorescence cymose; C contorted; A many, (fasciculate, fascicles opposite C); nectary 0; G opposite sepals [check], or median member adaxial, stigma papillate; ovules many/carpel, micropyle bistomal; fruit a septicidal or -fragal capsule; exotegmen with anticlinal walls sinuous, low, lignified; endosperm at most slight, embryo ± fusiform.

Evolution. This clade seems to have diverged in the Cretaceous-Albian, 111-100 million years before present, Clusiaceae (here sister to the rest of the clade) in turn diverging perhaps in the Cenomanian (104-)94(-92)/(95-)89(-87) million years before present (Davis et al. 2005a).

Chemistry, Morphology, etc. Given the likely phylogenetic relationships within this clade, anatomical studies of Bonnetiaceae are needed to clarify the apparent absence - or near absence - of secretory tissues. Takhtajan (1993) describes the pith as having secretory canals, as in Clusiaceae (cf. Baretta-Kuipers 1976). It is quite common for the calyx to be small relative to the corolla in bud, although clearly in taxa like Calophyllum and Clusia the bud is completely enclosed by the sepals.

Phylogeny. Relationships within the Bonnetiaceae + Clusiaceae + Podostemaceae group were unclear (see also Soltis et al. 1999b; Gustaffson et al. 2002; Davis et al. 2005b), although Wurdack and Davis (2009) have recently confirmed the paraphyly of Clusiaceae, necessitating the separation of Calophyllaceae (the old Clusiaceae-Kielmeyeroideae of versions 8 and before). Podostemaceae are strongly linked with Hypericum in particular, although the branch is rather long; the recognition of Clusiaceae in the very broad sense, i.e. including Hypericaceae, would again lead to a paraphyletic grouping. Bonnetiaceae + Clusiaceae + Hypericaceae seem to be a distinct group with several potential synapomorphies (some are lost or highly modified in Podostemaceae), and they are recovered even in morphological analyses (e.g. Luna & Ochoterena 2004 - Hypericaceae not in the study). Optimisation of some characters on the tree has become difficult.

Previous Relationships. Morphological data in particular (most of the features above) initially seemed to suggest a grouping of Elatinaceae + Bonneticaceae + Clusiaceae/Hypericaceae (e.g. see versions of this site prior to version 6). This was not a monophyletic group in Savolainen et al. (2000a), indeed, Ploiarium is there placed in Malvales (but see Wurdack & Davis 2009), although testa anatomy, etc., are strongly against such a position. Although analyses in Chase et al. (2002) weakly link Elatinaceae and Bonnetiaceae + Clusiaceae + Podostemaceae, the evidence now suggests that Elatinaceae are sister to Malpighiaceae (Davis & Chase 2004; Davis et al. 2005a; Tokuoka & Tobe 2006; Wurdack & Davis 2009), and there are some morphological data to support this.

Bonnetiaceae + Clusiaceae: ?

BONNETIACEAE Nakai   Back to Malpighiales

Evergreen shrubs; plant glabrous; (nodes 3:3); mucilage cells common; leaves spiral, involute [Keller 1996] or supervolute, margins minutely toothed by setae, petiole short; G [3-5], micropyle exostomal, style or separate styles long; cotyledons usu. small (-50% the embryo); n = ca 150 [Bonnetia cubensis].

3[list]/35: Bonnetia (30). Cambodia, Malesia (mostly Western), Cuba, South America. [Photo - Flower] [Photo - Flower]

• Bonnetiaceae may be recognised by their long-pointed buds, usually rather closely-set, spiral, short-petiolate and minutely-serrate leaves. The moderate-sized flowers are borne in cymose inflorescences, the corolla is contorted, the stamens are numerous, and the septicidal capsules contain many small seeds.

Chemistry, Morphology, etc. Bonnettia s.l. has trilacunar nodes, a mucilaginous epidermis, a foliar endodermis, and foliar sclereids; Archytaea and Ploiarium have unilacunar nodes and lack the distinctive epidermis, foliar endodermis and sclereids (Dickison & Weitzmann 1996). For Archytaea, Wawra de Fernsee (1886) shows a floral diagram in which both the five carpels and the stamen fascicles are drawn opposite the calyx. Ovule morphology in Bonnetiaceae appears to be unknown.

For chemistry, see Hegnauer (1969, as Theaceae), and for a general account, see Weitzman et al. (2006).

CLUSIACEAE Lindley, nom. cons.//GUTTIFERAE Jussieu, nom. cons. et nom. alt.   Back to Malpighiales

Trees or shrubs, (epiphytes, lianes); (vessel elements with scalariform perforations); leaves often flat (conduplicate), margins entire, linear canals +, (paired "stipular glands" on the stem); plant dioecious (perfect - Symphonia, etc.); flowers (3-)4-5-merous, K and C decussate (contorted), (0-)4-5(-8); A (5-)many, connate or not, (anthers with small glands); G [2-5(-12)], often opposite petals, (placentation apical, basal, parietal), style single or separate, usually short, stigmas much expanded to punctate and porose, not papillate, wet; (ovules 1-few/carpel); (fruit a berry); seeds few-many, (arillate), (exotegmen 0, then testa usu. much developed); embryo green or white, hypocotyl much enlarged, cotyledons minute.

14 [list]/595: Garcinia (240: esp. Old World), Clusia (300-400: entirely American), Chrysochlamys (55). Throughout the tropics (map: incomplete, from Gustaffson et al. 2007). [Photo - Staminate flower, Fruit.]

• Clusiaceae range from shrubs or trees and some are epiphytic; many are dioecious. The leaves are opposite and exstipulate, the blades are often thick, with entire margins, and usually have canals. An exudate is very common. The flowers have free sepals and petals and numerous stamens that are sometimes in fascicles. The fruit, when dehiscent, opens along the septal radius. The seeds are small to large, arils being known from many New World taxa, and the embryos are often apparently undifferentiated - the cotyledons are small to almost absent and the hypocotyl is enormous.

Evolution. For discussion on an interesting and well-preserved late-Cretaceous fossil from ca 90 million years before present that is possibly assignable to Clusiaceae, see Crepet & Nixon (1998). The seeds are described as being arillate, but the morphology of the aril is unlike that of extant Clusiaceae (it is adjacent to the seed, rather than surrounding it), and it may even be an aborted seed.

Variation in the androecium and gynoecium in Clusia and Garcinia is extreme. In Clusia, resins (polyisoprenylated benzophenones, mixed with fatty acids) are quite commonly a floral reward, and floral resin production may have evolved four times (and in Clusiella [Calophyllaceae]: Gustaffson & Bittrich 2002). Resins are an uncommon floral reward (but see also Dalechampia - Euphorbiaceae). In Symphonia pollen is caught in a droplet that exudes through the pore at the tip of the stylar branches, and is sucked back into the pore (Bittrich & Amaral 1996); the same unusual mechanism probably occurs in its immediate relatives which have similar stigmas.

Clusia is a very diverse genus and includes epiphytes and stranglers, and a number of species grow at elevations up to 3500 m in altitude (Gustafsson et al. 2007). For the general ecology of Clusia, see papers in Lüttge (2007). Crassulacean acid metabolism occurs in some of these epiphytes (e.g. Holtum et al. 2004), and its development may be promoted by phosphorous deficiency; whether or not the plant is mycorrhizal also affects the plant's phosphorous and carbon metabolism (Maiquetía et al. 2009).

Chemistry, Morphology, etc. Roots of Clusia, at least, have superficial phellogen, as is fairly common in epiphytic taxa in general. For the morphology of the diverse androecium in Garcinia and its immediate relatives, see Sweeney (2008). For chemistry, see Hegnauer (1966, 1989) and for general information, see Stevens (2006c).

Synonymy: Cambogiaceae Horaninow, Garciniaceae Bartling

Calophyllaceae [Hypericaceae + Podostemaceae]: leaves with gland dots or lines.

CALOPHYLLACEAE J. Agardh    Back to Malpighiales

Trees or shrubs; (vessel elements with scalariform perforations); schizogenous canals or cavities +; leaves (spiral, two-ranked), often flat (conduplicate; supervolute - Kielmeyera), (paired "stipular glands" on the stem; colleters 0); flowers 4-5-merous, C (contorted), (0-)4-5(-8); A not obviously fasciculate, many, (connate), anthers often with complex or simple glands; G (?1) [2-5], (placentation apical, basal), style (styles) +, usually long, stigmas much expanded to punctate, not papillate, wet; (ovules 1-few/carpel); (fruit a berry or drupe); seeds 1-many, (exotegmen 0); embryo green or white, cotyledons moderate sized to huge [Calophyllum, Mesua, etc.].

13[list]/460: Calophyllum (190), Kayea (70), Mammea (70), Kielmeyera (50). Throughout the tropics (map: in part see Stevens 1980 - blue is Calophyllum inophyllum). [Photo - Flower, Flower.]

• Calophyllaceae are usually trees that may be recognised by their spiral to opposite, exstipulate leaves with entire margins and pellucid dots or canals; there is often some exudate from the cut twig. The flowers have free sepals and petals and numerous stamens; the androecium is not obviously fasciculate, the anthers sometimes having large, apical glands. The fruit, when dehiscent, opens along the septal radius; the seeds range from small to large, and when large, they are made up almost entirely of two huge cotyledons.

Chemistry, Morphology, etc. Marila asymmetralis, alone in the whole family group, has obliquely monosymmetric flowers. The glands on anthers of genera like Caraipa are large, paired and crateriform, perhaps because the contents have beemn removed, while in other genera like Kayea they are small and rounded. Alternate-leaved genera form a clade; these genera also have capsular fruits, often with winged seeds, and their embryos have cotyledons with cordate bases. Although Calophyllum has opposite leaves, some species have seedlings with alternate leaves.

For chemistry, see Hegnauer (1966, 1989, as Guttiferae), for general information, see Stevens (2006c, as Clusiaceae), and for the distinctive foliar fibres of many species of Mammea, see Dunthorn (2009).

Phylogeny. Recent work suggest that Clusiella is to be included in this clade (Gustaffson et al. 2002). Its seeds and vegetative anatomy (including that of the root) are consistent with this position, although the flowers are a little odd, since they do indeed look like those of Clusia.

Previous Relationships. Many Theaceae also have spiral leaves, capsular fruits, winged seeds, and flowers with many stamens, and alternate-leaved Calophyllaceae seemed superficially to be similar and so used to be placed in that family. Another pseudoproblem caused by "intermediates" between groups which turn out not to be closely related at all (cf. Baretta-Kuipers 1976).

Hypericaceae + Podostemaceae: ovules tenuinucellate.

Divergence between Podostemaceae and Hypericaceae may have occurred in the Campanian, (82-)76(-69)/(74-)72(-66) million years before present (Davis et al. 2005a).

HYPERICACEAE Jussieu, nom. cons.   Back to Malpighiales

Shrubs or annual to perennial herbs; flavones, flavonols, biflavonoids, (ellagic acid) +; cork pericyclic; polyderm widespread; flowers 4-5-merous, C often contorted; A (5-)many, often fasciculate, centrifugal, anthers often with simple glands; G [3-5], (placentation parietal), style + to styles separate, (stigma not papillate), dry; (fruit a berry or drupe); seeds (5-)many, (exotegmen 0); embryo green or white, cotyledons moderate-sized (to 80% of the embryo); n = 6-12, etc.

9[list]/560: Hypericum (370), Vismia (55), Harungana (50). World-wide (map: from Hultén & Fries 1986; Meusel et al. 1978 - still incomplete for Africa). [Photo - Flower]

• Hypericaceae include numerous herbs or shrubs. Their leaves are opposite and with pellucid or dark dots; the androecium is often fasciculate; the stigma is sometimes obviously papillate; and the seeds are small (usually less than 4 mm long).

Evolution. The naptha-dianthrone hypericin may be synthesized by an endophytic fungus close to Chaetomium (Kusari et al. 2008).

Chemistry, Morphology, etc. For chemistry, see Hegnauer (1966, 1989, as Guttiferae), for androecial development, see Leins (2000), for secretory structures in vegetative parts of Hypericum, see Lotocka and Osinska (2010). For general information, see Stevens (2006c).

Phylogeny. Nürk and Blattner (2010) discuss relationships and evolution in Hypericum evident in an analysis of morphological characters; there seem to be groupings, albeit currently with little support.

Classification. Generic limits need attention, with those of Hypericum to be expanded and those of Harungana in particular probably to be restricted (Ruhfel et al. 2009, 2011; cf. in part Stevens 2006c, Nürk & Blattner 2010). For a monograph of Hypericum, see Robson (2010) and references.

Synonymy: Ascyraceae Plenck

PODOSTEMACEAE Kunth, nom. cons.   Back to Malpighiales

Annual (perennial) herbs of fast-flowing water, plant ± thalloid, stem root and leaf often not distinguishable, plant attached to substrate by haptera, basic construction sympodial; xanthones +; primary root 0, other roots (dorsiventrally flattened), photosynthetic, exogenous or endogenous, shoots endogenous [also at least sometimes flowers], branching extra-axillary; cork?; vessels usu 0; latex/resin cells +; epidermal SiO₂ bodies common; cuticle waxes 0; when leaves present spiral, opposite, 2- or 3-ranked, leaf base broad or not, stipules petiolar or 0; flowers also solitary, monosymmetric; P in single whorl; A 1-many (2 whorls, inner extrorse), filaments often basally connate (connective prolonged); pollen microechinate, infratectum granular; when G equalling P, opposite to it, style + (0), stigma linear; ovules (2-few/carpel), micropyle exostomal, nucellus plasmodial; embryo sac monosporic [from the subchalazal spore], tetranucleate [Apinagia type], no polar nuclei or double fertilisation; capsule ribbed, about the same size as the ovary, pedicels elongating; exotesta thick-walled, often mucilaginous, (exo- and) endotegmen lignified; suspensor [micropylar] haustorium +; cotyledons large; n = 10.

48[list]/270 - three subfamilies below. Usually tropical, esp. America, many genera are monotypic.

1. Tristichoideae Engler

Xanthones?; (root cap 0); (stem flattened); stomata?; P 3, (connate); A (1-)3, anthers sagittate, pollen pantoporate, G [3], integuments develop simultaneously; hypocotyl 0.

3/4-10. India-Australia, but Tristicha trifaria in Africa and America (map: from van Royen 1953; Cusset & Cusset 1988a; Kito & Kato 2004; Kato 2009).

Synonymy: Philocrenaceae Bongard, Tristichaceae J. C. Willis

Weddellinoideae + Podostemoideae: G [2], with apical septum.

2. Weddellinoideae Engler

Plant with scales; flowers single, terminal; P (4) 5 (6), 1-veined; A 5-25, anthers X-shaped, pollen ?development, smooth, ?infratectum?, integuments develop simultaneously, stigmas globose; capsule not ribbed; tegmen (?layer) thick walled; hypocotyl +.

1/1: Weddellina squamulosa. N. South America (map: from van Royen 1953).

3. Podostemoideae Engler

Shoot apical meristem 0; apical meristems of root on the underside of the thallus, (roots exogenous); ("laticiferous" tubes +); stomata 0?; leaves ± endogenous, lacking normal epidermis, often distichous, ensiform, but bifacial, (digitate), (some leaves dithecous [double-sheathed, one sheath on both sides]), (leaves with axillary branches, not dithecous - Thelethylax), (stipulate); flowers or groups of flowers enveloped by a non-vascularized spathella [= ?calyx], (spathella of non-terminal flower open - Diamantina), (flowers inverted in bud - some African taxa); P 2-25, often 2-3 on one side, lobes narrow, sometimes replaced by stamens; A 1-3(-many), often sagittate, (extrorse); (microsporogenesis successive [tetrads tetragonal]); pollen often in dyads, (a)calymmate, 3-5-colpate; G also [3(-7)], (unilocular), gynophore + (0), style short, branches long, (2 styluli - Diamantina); ovule with outer integument that develops first, (micropyle naked); (embryo sac bisporic [Polypleurum and Podostemon types]; polar nucleus degenerates, no double fertilization); radicle 0 (plumule 0; cotyledon 1); (n = 14). Floral Diagram.

45/260: Apinagia (50: perhaps paraphyletic, see Philbrick et al. 2001). Pantropical (map: from van Royen 1951; van Steenis 1972; Kato 2009). [Photo - Marathrum Flower]

Synonymy: Marathraceae Dumortier

• Podostemaceae are the quintessential aquatic angiosperm with a vegetative body so highly modified that conventional terms cannot be used to describe it - the plant body of many taxa is best described as thalloid or fucoid, although some species look like a demented apiaceous plant with two-ranked leaves. Many species are annual, and flowers or groups of flowers are often enveloped in a spathella; the capsule is septicidal, and the small seeds are often mucilaginous.

Evolution. Although there have been suggestions that Podostemaceae are attached to rocks by means of a special glue that they produce, it is more likely that it is materials in a biofilm produced by associated cyanobacteria that attach the plant to the substrate. There are hooked hairs on the lower side of the thallus that stick to the cyanobacterial filaments and associated biofilm. Indeed, these cyanobacteria may even produce nitrogen used by the plant; Podostemaceae usually grow in oligotrophic rivers flowing over gneiss or granite, being absent in rivers over limestone (Jäger-Zürn & Grubert 2000). For germination and establishment, see Grubert (1970, 1976); mucilage from the testa firmly attaches the seed to a rock.

Some Podostemaceae self pollinate, and it is possible this may take place by the pollen tubes growing through the tissue of the flower to the ovules (Sehgal et al. 2009).

Interpretations of the plant body of Podostemaceae, the "thallus", vary, and saltational evolution has been invoked to explain how very different and distinctive morphologies in related taxa have evolved (Koi & Kato 2010). It has been suggested that it is a highly modified but ultimately fairly conventional plant body (Jäger-Zürn 2005), or that it is a plant structure that cannot be compared with any other - indeed, Podostemaceae have sometimes been set apart from all other angiosperms (e.g. Cusset & Cusset 1988b). Since Podostemaceae are now being linked with Hypericaceae, detailed studies of the growth of the latter may provide clues for the evolution of the growth of the former, particularly building on the developmental studies of Katayama et al. (2010).

Podostemaceae with ribbon-like roots have opposite branching, those with a crustose or foliose growth form have endogenous shoots born singly on the upper surface. The evolution of the remarkable flattened roots of some Podostemoideae and Tristichoideae, which lack caps and have meristematic regions on both sides of the root, from the more ordinary-looking roots found in Weddelinoideae and some other Tristichoideae has been carefully documented by Koi et al. (2006). The exogenous or superficial origin of roots of some Podostemoideae is very unusual, since roots are normally endogenous, being initiated inside the pericycle; Cladopus has both exogenous and endogenous lateral roots (Rutishauser & Pfeifer 2002). Some taxa also have shoots arising endogenously in the cortex (e.g. Moline et al. 2007). Whatever their origin, roots often have root caps.

The apex of the stem has a tunica-corpus construction. There is some controversy over whether normal axillary branching occurs or not (e.g. Rutishauser et al. 2005; Jäger-Zürn 2009a). Dithecous leaves usually terminate growth of the axis that bears them; the leaf bases have two concave sheaths facing in opposite directions and in the axils of each a flower or branch bud arises (Rutishauser et al. 2003); for the optimisation of these dithecous leaves on a phylogeny of Podostemoideae, see Moline et al. (2007: note the adaxial position of the prophyll of the axillary dithecal vegetative shoot illustrated). Jäger-Zürn (2009b) also depicts the dithecous leaf as being adaxial on the axillary shoot that bears it. Katoyama et al. (2010) found from gene expression patterns in two Podostemoideae that it is almost as if a determinate "leaf" caps the indeterminate stem, new leaves/branches developing endogenously from the base of the "leaf"; since separation of the young "leaves" is by cell death, they will lack an epidermis, hence, perhaps, the absence of stomata in the subfamily - although they might be found on the flowers, in which there is more normal development (e.g. Katayama et al. 2008).

The nature of the spathella is unclear. Unlike bracts in Podostemoideae examined, its development is that of a "typical organ of leaf homology" (Katayama et al. 2010, see also Katayama et al. 2008), although Eckardt and Baum (2010) suggest more specifically that it is calycine. However, if there is more than one flower per spathella, then its nature may need re-examination. Although the embryo usually lacks a plumule and radicle, these were recently reported for Malaccotristicha sp. (Kita & Kato 2005), and the seedling of Zeylanidium olivaceum has a hypocotyl; more information is needed on embryo morphology (but see Koi & Kato 2010).

Chemistry, Morphology, etc. Grubert (1976) noted distinctive contents in cells of young plants of several Podostemaceae. Some species of Dalzellia (Tristichoideae) have a cupule at the base of the pedicel that is formed by leafy shoot axes (Mathew et al. 2001). Tristicha - A 1, adaxial, median carpel abaxial? (Schnell 1998). The position of the stamens may suggest an obliquely monosymmetric flower (Cusset & Cusset 1988b), while Razi (1955; see also Endress & Matthews 2006a) described the flowers of Zeylanidium olivaceum, which have a spathella, two stamens and two carpels, as being monosymmetric. There is sometimes an apical meristem in the vegetative body of Podostemoideae and the spathella may be produced by the connation of two foliar structures (Jäger-Zürn 2005b). The outer integument develops early and the nucellus protrudes beyond the inner integument. The plasmodial nucellus has been described as a pseudo-embryo sac. Tobe and Raven (2011) describe the tegmen as being unspecialised.

There are different pathways by which the nucellus becomes plasmodial are discussed by Jäger-Zürn (1997). There is considerable variation (and a corresponding amount of controversy) over the development of the embryo sac in particular, perhaps especially in Weddellina (see e.g. Battaglia 1971; Arekal & Nagendran 1975, 1977a, b; Nagendran et al. 1976; Murguía-Sánchez et al. 2002; Sehgal et al. 2011). Is it mono- or bisporic, and does it have 3, 4 or 5 cells at maturity? However, there is general consensus that there is no double fertilisation.

Much information is taken from Rutishauser (1997); see also Hegnauer (1969, 1990), Contreras et al. (1993) and Kato et al. (2005) - all these chemistry, Graham and Wood (1975), Cusset and Cusset (1988a), Rutishauser and Huber (1991), Lobreau-Callen et al. (1998: pollen), Rutishauser and Grubert (1993, 2000), Passarelli (2002: pollen), Suzuki et al. (2002: seedlings), Sehgal et al. (2002: seeds, etc.), Ameka et al. (2002: general), Koi and Kato (2003: roots, 2007: hypotheses on nature of shoots and leaves), Jäger-Zürn (2003: apical septum, 2005b: interpretation of the thalloid plant body, 2007: shoot apex; 2011: possible new characters), Rutishauser et al. (2004: Diamantina), Rutishauser and Moline (2005: emphasis on "homology"), Jäger-Zürn et al. (2006: microsporogenesis), Cook and Rutishauser (2006: general), Sehgal et al. (2007: organ identity), Jäger-Zürn (2008: Thelethylax), Kato (2008: general), Thiv et al. (2009: African Podostemoideae), Ghogue et al. (2009: Djinga, morphology), Koi and Kato (2010: vegetative body, Hydrodiscus et al.), and de Sá-Haiad et al. (2010: floral morphology Podostemon).

Phylogeny. Podostemoideae + Weddellinoideae are sister to Tristichoideae, all branches having very strong support (Kita & Kato 2001; see also Kita 2002: phylogeny and morphology). See Moline et al. (2007) for the phylogeny and evolution of African Podostemoideae, Koi and Kato (2010) that of Asian Podostemoideae, and Koi et al. (2009) for that of Tristichoideae (and the description of a distinctive new genus), and Tippery et al. (2011) for that of New World Podostemoideae. The recently-described Diamantina appeared to be sister to all other Podostemoideae (Ruhfel et al. 2009), although that genus was not studied by Tippery et al. (2011), who found Podostemon and a paraphyletic Mourera as successively sister to the rest. Morphological analyses allowed the recovery of a few small generic clades, but molecular data resolved quite a number of nodes (Tippery et al. 2011).

Classification. For generic limits in some African Podostemoideae, see Thiv et al. (2009).

Previous Relationships. Prior to molecular work, systematists were largely at a loss as to where the relationships of Podostemaceae were to be found. The micropylar suspensor haustorium seemed like that of Crassulaceae, and a relationship between the two families has been proposed, as by Les and Philbrick (1996) and Ueda et al. (1997a), but very different positions have also been suggested (Cusset & Cusset 1988b and refs.). The xanthones are similar to those both of Gentianaceae (in the -6-0-glucosides) and of Clusiaceae (in the isoprenyl substitutions).

Centroplacaceae [Elatinaceae + Malpighiaceae]: K persistent in fruit.

Phylogeny. for relationships in this area, see Zhang et al. (2009a, 2009b, 2010) and Wurdack and Davis (2009).CENTROPLACACEAE Doweld & Reveal   Back to Malpighiales

Inflorescence branched, pedicels articulated; A 5, opposite sepals; styles widely diverging, stigmas little expanded; ovules 2/carpel, collateral; capsule loculicidal, one seed/loculus; exotegmic cells ribbon-shaped, thick-walled, arils exostomal, sheet-like; embryo short.

2[list]/6. West Africa, Indo-Malesia.

1. Centroplacus

Tree; chemistry?; cork?; vessel member perforations?; sclereids +; stomata anisocytic; leaves two-ranked, toothed, stipules cauline; plant dioecious; flowers small, disc? lobes alternating with K and outside A, staminate flowers: connective well developed, dehiscence oblique-apical, pollen psilate, perforate, pistillode +; carpellate flowers: C 0, ?staminodes minute; G [3], ovules subapical, epitropous; fruit a septicidal (and loculicidal) capsule opening from the base; seed carunculate; exotesta rather tall, outer wall thickened, mesotegmic cells flattened and at right angles, endotegmen ± thick-walled; n = ?

1/1: Centroplacus glaucinus. W. Africa.

2. Bhesa

Trees; chemistry?; (cork mid-cortical); vessel elements with scalariform perforation plates; paratracheal parenchyma +; nodes 5:5; calcium oxalate as crystals [?always]; petiole with bundles forming a U or flattened-annular, 2-3 medullary bundles, (also wing bundles); stomata laterocylic; leaves spiral, conduplicate, entire, petiole ± pulvinate apically, stipules almost encircling the stem, colleters +; inflorescence racemose; C contorted; A extrorse to introrse, pollen finely striate, nectary lobed or not; G [2], ovules basal, erect, apotropous, micropyle exostomal, outer integument 6-8 cells across, inner integument 4-5 cells across; seed arillate, aril exostomal-funicular; exotegmic cells massive; n = ?; germination epigeal.

1/5. Indo-Malesia (map: from Ding Hou 1962).

• Although hardly very distinctive, Centroplacus is a dioecious evergreen tree with serrate and stipulate leaves. It can be recognised by its branched inflorescences of small flowers; the staminate flowers have only five stamens in which the connective is well developed and the anthers dehisce by two oblique-apical slits.

• Bhesa species are usually evergreen trees with stipulate leaves (the stipules almost surround the stem) the blades of which are entire and have strong, regularly ascending secondary veins and distinctive closely scalariform tertiary venation; there is a pulvinus at the apex of the petiole. The flowers are small and are rather undistinguished, but the fruits are strongly bilobed and have arillate seeds.

Evolution. Centroplacaceae may perhaps be sister to Ctenolophonaceae, diverging in the Cretaceous-Albian 111-100 million years before present ([109.6-]101.8[-96.6]/[97.1-]91.0[-88.1] million years before present: Davis et al. 2005a).

Bhesa is reported to be ectomycorrhizal (Smits 1994).

Chemistry, Morphology, etc. The ribbon-shaped exotegmic cells of Bhesa are longer than those of Centroplacus, and its integument is much thicker. For general information, see Pierre (1894), Ding Hou (1962: as Celastraceae) and Wurdack and Davis (2009). For seed and vegetative anatomy of B. ceylanica, see Jayasuriya & Balasubramaniam 3107.

The endostome of Centroplacus is lignified and more or less protruding. For more information about Centroplacus, see Forman (1966: general), Stuppy (1996: seed anatomy and good discussion, not Euphorbiaceae s.l.), Tokuoka and Tobe (2001: seed anatomy, Euphorbiaceae-Phyllanthoideae, but with some doubt), and Radcliffe-Smith (2001: generic description).

Although Centroplacus glaucinus has often been placed in Pandaceae (Takhtajan 1997; Mabberley 1997), Webster (1994) and Radcliffe-Smith (2001) include it in Euphorbiaceae, but only with hesitation and with little certainty as to where it should be placed within the family. There is no obturator, unlike Euphorbiaceae. In a molecular study by Wurdack et al. (2004) Centroplacus is associated with Pandaceae, although with very little support, however, in Davis et al. (2005a) it is separate from Pandaceae and weakly associated with Ctenolophonaceae. Recognising the genus as a family seems most reasonable.

Bhesa was distinctive in morphological analyses of Celastraceae, in which it had up to now been included (Simmons & Hedin 1999; Matthews & Endress 2005b), if sometimes with some doubt (e.g. Pierre 1894 [he thought it might be in a separate family]; Metcalfe & Chalk 1950; Ding Hou 1962). Its huge stipules, distinct styles, vessels with scalariform perforation plates, etc., were somewhat out of place there, although Celastraceae were so heterogeneous that a strong case could not be made for its removal. The seed coat, with its massive exotegmic cells, is also very different, as is its pentalacunar nodes. Zhang and Simmons (2006) recently found that it fell among the few Malpighiales they included in their analysis of Celastrales, and Ken Wurdack (pers. comm.) suggests that a position around about here may be appropriate.

Elatinaceae + Malpighiaceae: vessel elements with simple perforation plates; sieve tube plastids lacking starch and protein inclusions; leaves opposite, with glands[?], (margins with teeth); inflorescence cymose; flowers with inverted orientation; nectary 0; when G 3 median member adaxial; fruit septifragal; endosperm slight; x = 6.

Evolution. The common ancestor of these two families may have diverged towards the beginning of the Cretaceous-Albian 111-100 million years before present, the Malpighiaceae and Elatinaceae themselves separating towards the end of this period ([113-]98[-89]/[100-]89[-85] million years before present: Davis et al. 2005a).

Depending on the interpretation of variation, both the evolution of monosymmetric flowers and flowers with an inverted orientation can be pegged to this node (Zhang et al. 2010).

Chemistry, Morphology, etc. Vega et al. (2002) suggest that the laticifers of Galphimieae might be a symplesiomorphy with Euphorbiaceae, although laticifers are not an apomorphy of that family (see below); I know nothing of the composition of the latex. For the foliar glands and resin and latex production in Elatinaceae and Malpighiaceae, neither well understood, see Vega et al. (2002) and Davis and Chase (2004). Zhang et al. (2009a) surmised that the ancestor of [Elatinaceae + Malpighiaceae] might be monosymmetric.

For relationships between Malpighiaceae and Elatinaceae, see Davis and Chase (2004), Tokuoka and Tobe (2006), Korotkova et al. (2009), Wurdack and Davis (2009), Wang et al. (2009), etc.

Previous Relationships. It had been suggested that Malpighiaceae were rather weakly associated with Peridiscaceae and were perhaps near Clusiaceae et al. (Chase et al. 2002); for the current position of Peridiscaceae, here in Saxifragales, see e.g. Davis and Chase (2004).

ELATINACEAE Dumortier, nom. cons.   Back to Malpighiales

Herbs to subshrubs of moist/wet habitats; flavonols, ellagic acid +; plant resinous; (cork from inner cortex); nodes 1:1; mucilage cells +; leaves with colleters, stipules minute, scarious; flowers (single), (2-)5-6-merous, K free to connate, C contorted; stamens = and opposite sepals, or 2x K; (pollen trinucleate - Elatine), G [2-5], opposite sepals, stigma papillate; ovules many/carpel, micropyle zigzag, several megasporocytes; fruit capsular; exotegmen with anticlinal walls sinuous, low, lignified; embryo ± fusiform; n = (9); duplication of CYC genes.

2[list]/35: Bergia (25), Elatine (10). Worldwide, most tropical, not arctic (map: from Meusel et al. 1978; FloraBase 2006).

• Elatinaceae are often herbaceous plants of moist habitats with opposite, more or less toothed leaves with small, paired, scarious stipules. The cymose inflorescences have small flowers with papillate stigmas.

Chemistry, Morphology, etc. Eichler (1878) draws three-merous flowers of this family with the odd sepal abaxial, i.e., in the monocot position, and Zhang et al. (2010: Supplement 1) consider that this orientation also occurs in flowers of the 5-merous Bergia texana. Some embryological data are taken from Tobe and Raven (1983b).

Synonymy: Cryptaceae Rafinesque

MALPIGHIACEAE Jussieu, nom. cons.   Back to Malpighiales

Lianes to trees; ellagic acid 0; (cork ?near endodermis); secondary thickening often anomalous; pits vestured; (nodes 1:1); petiole bundle arcuate; cuticle waxes as rosettes; stomata usu. paracytic; branching from current flush; hairs unicellular, ± T-shaped, surface rough; leaves (spiral), glands common, abaxial or petiolar, stipules cauline, intrapetiolar [trees, shrubs] and petiolar (0); inflorescence various; flowers poly- or obliquely monosymmetric, K with large paired abaxial oil glands (0 - esp. Old World taxa), C clawed, often crumpled in bud, often fringed, one adaxial-lateral often different to the others; A (2; = and opposite sepals) 10, obdiplostemonous, (15), often basally connate; tapetal cells multinucleate; G [(2) 3(-5)], (inferior), styles +, (style single), stigmas asymmetrically capitate, dry; ovule 1/carpel, apical, apotropous, micropyle various, nucellar beak +, embryo sac often tetrasporic, 16-nucleate (bisporic); K and A often persistent in fruit (K accrescent, wing-like; separating into mericarps); (exotegmen fibrous - Thryallis), endotegmic cells (elongated), lignified; chalazal endosperm haustoria +, (embryo curved); duplication of CYC genes.

68[list]/1250 - two groups below. Tropical and subtropical, especially American (map: C. C. Davis, from Arènes 1957). [Photo - Flower, Flower, Fruit.]

1. Malpighioideae Burnett

Pollen globally symmetrical [4-polyporate]; style various, stigma usu. not terminal; fruit winged, (bristly, unwinged); n = (9) 10.

Malpighia (?130), Heteropterys (120), Stigmaphyllon (100), Banisteriopsis (90), Bunchosia (55), Mascagnia (50), Malpighia (40). Tropical and subtropical, especially the Americas.

2. Byrsonimoideae W. R. Anderson

(Articulated laticifers + - Galphimieae); style subulate, stigma terminal.

Byrsonima (150). American Tropics.

• Malpighiaceae are a distinctive family, with their usually opposite, entire leaves with paired stipules (these vary in position). The unicellular hairs are T-shaped, often a characteristic brown, and there are often conspicuous flat glands on the lower surface of the leaf blade or on the petiole. The flowers are characteristic: 4 or 5 sepals often have paired glands, the petals are strongly clawed and are crumpled in bud, an axially-positioned petal often being a banner petal, and there are usually three carpels, each with a single ovule. The sepals and filaments often persist at the base of the fruit, which is often a samara with a variable number of wings.

Evolution. An origin of the family in South America during the Late Cretaceous (ca 68 million years before present) has been suggested, with several - it now appears to be nine - subsequent dispersal events to the Old World followed by the loss of oil secretion by the sepals (Davis et al. 2002a, b, 2004; esp. Davis & Anderson 2010). Malpighiaceae are known fossil from the Northern Hemisphere, e.g. from the Eocene Claiborne Formation in Tennessee, U.S.A., in deposits ca 34 million years old (Taylor & Crepet 1987).

Malpighiaceae are one of the three major groups of lianes in the New World tropics (see also Bignoniaceae-Bignonieae and Sapindaceae-Sapindoideae).

The family is noted for having oil flowers (e.g. Renner & Schaefer 2010 and references), oil being secreted by paired calyx glands (epithelial elaiophores) and removed by the legs of the bees - several genera of Apidae and Centridini-Anthophoridae are involved. The latter, at least, grasp the narrow base of the banner petal of the inverted monosymmetrical flowers with their mandibles as they collect the oil; this banner petal is often distinctively coloured, and may change colour as it ages. Oil is secreted in New World taxa only. In some Malpighiaceae growing in the Old World the "oil" glands may secrete nectar (Vogel 1974, 1990), although in most pollen is the only obvious reward (Davis & Anderson 2010). There the orientation of the flowers has sometimes reverted to the normal condition for a core eudicot with the odd petal abaxial, Zhang et al. (2010) suggesting that this is because of a 36^o rotation of the flower. Monosymmetry is associated with a monocot-type orientation of the flower and duplication(s) of CYC genes (Zhang et al. 2010), although there is no local genome duplication. Flowers of Old World Malpighiaceae tend to be more or less polysymmetric, the petals are less strongly clawed, and the style branches longer and more widely spreading (Davis & Anderson 2010 for illustrations). Buzz pollination may also occur in Malpighiaceae (Sigrist & Sazima 2004).

The flowers of Oncidiinae orchids may mimic those of New World Malpighiaceae, and sometimes even provide fatty acids as a reward that are similar to those of Malpighiaceae (Reis et al. 2007).

Self-fertilization is common in species of Gaudichaudia, Janusia and relatives; it occurs by pollen tubes growing through the tissues of the flower to the embryo sac (Anderson 1980).

Chemistry, Morphology, etc. Acridocarpus has spiral, exstipulate leaves and an inferior ovary with only two carpels fertile. Some species of Stigmaphyllon have leaves with palmate venation and toothed margins; some taxa, especially when young, have almost fimbriate lamina margins, albeit distantly so (the fimbriae are ca 4 mm long). Stipules are very diverse, being petiolar in Hiraea and cauline in many vines and also in Malpighia; in the latter genus they may be lobed or toothed. Apomixis - nucellar polyembryony - is common.

Testa anatomy may repay investigation. In Mascagnia macrodisca there is a layer of thin-walled, slightly elongated cells with brown contents over a layer of more or less isodiametric, lignified cells with somewhat more thickened and straight anticlinal walls; the latter layer has a "frosted" appearance; the origin of these cell layers is not known (pers. obs.). Given that the main protective part of the propagule is not the seed coat, testa and tegmen may be rather reduced. Nevertheless the fibres of the endotegmen may be quite conspicuous (Silva & Trombert 2006). Since fibres in other Malpighiales are exotegmic and Elatinaceae also have exotegmic seeds, what is going on in Malpighiaceae is unclear.

Some information on chemistry is taken from Hegnauer (1969, 1989: iridoids have been reported from Stigmatophyllum) and on fruit and seed is taken from Takhtajan (2000). C. Anderson et al. (2006 onwards) provide general information, especially phylogeny and nomenclature, for the whole family.

Phylogeny. Information on relationships within the family is taken from Davis et al. (2001) and Cameron et al. (2001); Old World Malpighiaceae occur in at least six clades of Malpighioideae.

Previous Relationships. Malpighiaceae were included in Vochysiales by Takhtajan (1997).

Peraceae [Rafflesiaceae + Euphorbiaceae]: vessel elements with simple perforation plates; flowers small, imperfect; G [3], 1 apical epitropous pendulous ovule/carpel, nucellar cap + [unknown in Peraceae], styles ± separate; fruit a septicidal capsule/schizocarp, also splitting from the columella and loculicidally, mesocarp often separating from endocarp; seeds large, micropylar caruncle + (0); cotyledons longer and broader than radicle.

Chemistry, Morphology, etc. Note that many of the features mentioned above are lost in Rafflesiaceae. The exotegmen there is described as having U-shaped thickenings, and the exotegmen of some Peraceae can also look U-shaped in transverse section (see illustrations in Tokuoka & Tobe 2003).

Phylogeny. Determining the phylogenetic relationships of Rafflesiaceae has been difficult, as has that of many parasitic groups. Apart from the distinctive and often hard-to-interpret morphologies of families that have been included in Rafflesiales - Rafflesiaceae, Apodanthaceae, Cytinaceae and Mitrastemonaceae - molecular analyses have been problematic in part because of the very long branches in some genes and the general problem of obtaining suitable sequences from holoparasites (e.g. see results from analysing sequences of the mitochondrial atp1 gene - Nickrent et al. 2004a). Indeed, when representatives of all four families are included, an apparently monophyletic Rafflesiales s.l. may still be recovered (Nickrent et al. 2004a); Nickrent (2002) had suggested that Rafflesiaceae themselves might be close to Malvales. However, other analyses, including those in which not all members of the erstwhile Rafflesiales are included at one time, suggest a break-up of the group, with Rafflesiaceae here, Mitrastemonaceae in Ericales, Cytinaceae in or near Malvales, and Apodanthaceae in Cucurbitales (Barkman et al. 2004; Davis & Wurdack 2004; Nickrent et al. 2004a; Davis et al. 2007; Filipowicz & Renner 2010).

Barkman et al. (2004a) sequenced the mitochondrial gene, matR, of Rafflesia and found a strong association with Malpighiales (see below for previous placements of Rafflesiaceae). Although sampling within Malpighiales (only three taxa with parietal placentation were studied) and other rosids was poor, Barkman et al. (2004) noted that the flowers of Rafflesia could be interpreted as having a number of features in common with those of Passifloraceae, including a corona (called a diaphragm by students of Rafflesiaceae), androgynophore, parietal placentation (but this is common in echlorophyllous parasites), etc. (but, as Nickrent et al. [2004a] point out, the "homology" of these structures needs careful examination). Davis and Wurdack (2004: two nuclear, one mitochondrial [matR] genes), with considerably more extensive sampling, but also confirming a position in Malpighiales, favoured a position closer to Ochnaceae, Clusiaceae and their relatives, and tenuinucellate ovules are common there, too - however, it is quite common for holoparasitic taxa to have tenuinucellate ovules... Many of the analyses carried out by Nickrent et al. (2004a) also suggested a position of Rafflesiaceae in or near Malpighiales. Most recently, Davis et al. (2007), using largely mitochondrial genes, exemplars of all families of Malpighiales, and a good sample of Euphorbiaceae (including three of the four genera of Peraceae, Chaetocarpus only excluded, Euphorbiaceae-Cheilosioideae also included), located Rafflesiaceae within Euphorbiaceae and with quite good support (see also Wurdack & Davis 2009). Splitting Peroideae from the other Euphorbiaceae - which actually makes the latter more homogeneous in fruit and testa anatomy - and keeping Rafflesiaceae seems reasonable, there being little enthusiasm for including a Rafflesioideae within Euphorbiaceae.

PERACEAE Klotzsch   Back to Malpighiales

Shrubs to trees; cork cambium?; nodes?; petiole interrupted arcuate to annular, complete annular (also with central plate and wing bundles); stomata?; leaves spiral, margins entire, venation pinnate, stipules small or 0; staminate flowers: C (unguiculate; 0); A 2-8, (connate, extrorse); pistillode 0; carpellate flowers: (K 0, C 0); staminodes 0; ovule with both integuments 3-6 cells across; fruit septa membranaceous and without visible vascularisation, (valves connected at base), perianth [when present] persistent; seeds carunculate or arillate, very shiny; exotesta palisade, lignified, exotegmen tracheoidal, (palisade - Pogonophora); endosperm copious; n = ?

5/135: Clutia (70), Pera (40). Pantropical, probably not E. Malesia (one doubtful report) (map: inaccurate, see van Welzen 1994).

Evolution. Myrmecochory may predominate in this clade (Lengyel et al. 2009).

Chemistry, Morphology, etc. Pogonophora has adaxially barbellate petals. Style branches are variable in this group, being very short to longer and bifid. The seeds are described as having arils by Tokuoka and Tobe (2003). Neither wood anatomy nor pollen morphology are distinctive (Nowicke et al. 1998; Hayden & Hayden 2000), however, members of the family are variously described as having lysigenous radial canals in the wood, laticiferous cells, and elongated cells with brown contents. Many details of anatomy, and in particular floral development, ovule morphology, etc., are poorly known.

The anatomy of the seed coat of Peraceae is distinctive compared to that of Euphorbiaceae s. str. - this from an earlier version of /APweb/: "Tokuoka and Tobe (2003) note some Acalyphoideae with a distinctive seed coat anatomy - a more or less tracheoidal exotegmen - unlike that of all other Euphorbiaceae (minus Phyllanthaceae, etc). Interestingly, all the taxa involved belong to other families or are in Euphorbiaceae-Peroideae. These are sister to other Euphorbiaceae, and the distinctive exotegmen structure is more like that common in other Malpighiales. So it is possible that this is plesiomorphic, whereupon the palisade exotegmen of Pogonophora is a parallelism..." The seed coat anatomy of Trigonopleura is unknown.

For pollen, see Nowicke et al. (1998), for wood anatomy, see Hayden and Hayden (2000); for seed coat anatomy, see Tokuoka and Tobe (2003); for general information, see Webster (1984) and Radcliffe Smith (2001).

Phylogeny. Tokuoka and Tobe (2006) question the inclusion of Pogonophora in this clade; indeed, if it is to be included and is sister to other Peraceae, then mapping seed coat evolution on the tree becomes a bit tricky. For a comprehensive checklist and bibliography, see Govaerts et al. (2000, in Euphorbiaceae).

Previous Relationships. Although Airy Shaw (1976) recognised Peraceae as separate from Euphorbiaceae, his Peraceae included only Pera, a genus long considered very distinctive within Euphorbiaceae, even if rarely separated from it. Esser (2003) drew attention to the distinctiveness of the whole group.

Rafflesiaceae + Euphorbiacaeae: ?

RAFFLESIACEAE Dumortier, nom. cons.   Back to Malpighiales

Stem or root parasites, endophytic, rhizomes and roots 0; vessel elements?; sieve tube plastids lacking starch and protein inclusions; cuticle wax crystalloids 0; inflorescences various, or flowers single; flowers medium to huge; P uniseriate, 5/10/16+-lobed, (valvate), with an annular diaphragm [?corona], the margins incurved, (absent - Rhizanthes), (nectary on distal part of perianth - Rhizanthes); staminate flowers: A 12-40, adnate to central column [pistillode, = gynostemium], extrorse, anthers sessile, bisporangiate/monothecal to polysporangiate, pores terminal; pollen inaperturate, atectate; carpellate flowers: ovary inferior, nectary at base of style, carpel margins closed by postgenital fusion and secretion, placentation laminar-parietal, many tenuinucellate ovules/carpel, micropyle (exo-)endostomal, nucellar epidermis persists, style very short, stigma on outer margin or underside of disc-shaped structure; fruit baccate; seed in two parts, that covered by the testa not enveloping the embryo, exotegmic cells with U thickenings; endosperm slight, embryo undifferentiated; n = 11, 12.

3[list]/20: Rafflesia (16). S. China, Assam, Bhutan, Thailand, W. Malesia (map: from Meijer 1997). [Photo - Flower.]

• Rafflesiaceae s. str. are stem or root parasites on Vitaceae lacking both rhizomes and roots. The large to massive flowers are imperfect and with a uniseriate, connate perianth; there are 12-40 extrorse stamens adnate to a central column in the staminate flowers and the carpellate flowers have an inferior ovary.

Evolution. The age of stem Rafflesiaceae may be (109.5-)95(-83.1) million years, that of the crown group (95.9-)81.7(-69.5) million years ago, however, diversification with each genus did not begin until very much later, that in Rafflesia at a mere (15.1-)11.8(-9.2) million years being the first - there may have been an extinction event immediately prior to this (Bendiksby et al. 2010, which see for further dates, 95% highest posterior densities; see also Barkman et al. 2008). Note that if Sapria split off from other Raffflesiaceae ca 81.7 million years ago (Bendiksby et al. 2010) there must have been a major reorganization of the plant body in less than 15 million years.

There was a ca 79-fold increase in flower size during the evolution of stem-group Rafflesiaceae over a period of ca 46 million years, size increase in the subsequent ca 60 million years has been much more modest, an increse perhaps linked to the adoption of sapropmyophily (Davis et al. 2007, 2008). However, in a more extensive study of Rafflesia, Barkman et al. (2008) suggested that there had been very considerable changes in flower size even within the last 12 million years or so, the age of crown group Rafflesia, with repeated both considerable increases and moderate decreases in flower size from an ancestral (very approximate) 29 cm across (Barkman et al. 2008).

The flowers of at least some Rafflesiaceae are thermogenic (Seymour 2001) and pollination, where known, is by flies (Davis et al. 2008).

Rafflesia is parasitic on species of Tetrastigma (Vitaceae), an asociation that has evolved more than once (P. Chen et al. 2011). Davis and Wurdack (2004) found that the sequence of another mitochondrial (nad1B-c) gene they sequenced strongly suggested a relationship between Rafflesiaceae and Vitaceae; the presence of this gene in Rafflesiaceae they reasonably thought was caused by horizontal gene transfer from Vitaceae.

Chemistry, Morphology, etc. The plant is tanniniferous (Gottlieb et al. 1989). Although there are stomata in Rafflesia, they are clearly abnormal, with three or more guard cells (Cammerloher 1920).

What the perianth represents is still unclear. If Sapria is interpreted as having a biseriate perianth (the spreading lobes of the flower), then the annular diaphragm in the middle is "coronal" in nature. However, in Rafflesia the tubular structure below the diaphragm seems to have an inner and outer portion, suggesting that the spreading lobes represent the calyx and the diaphragm the corolla (D. Boufford, pers. comm.)... Furness and Rudall (2004) note a very distinctive combination of microsporogenesis and pollen morphology for the family, but for pollen morphology, see also Blarer et al. (2004). The outer integument, when present, is one cell layer thick, but it is not easy to interpret the ovule (see Solms-Laubach 1874; Ernst & Schmid 1913 for more details). Although the funicle is bent, the integument is not adnate to it; in taxa with a single integument, there is a swelling on the chalaza, perhaps an indication of the other integument. During germination of some Rafflesia, at least, the seed is anchored onto the host by sticky endosperm tubules and also the embryonal primary haustorium, the whole thing looking rather like a T4 bacteriophage (Arekal & Shivamurthy 1976).

For information, see Harms (1935a: general), Takhtajan et al. (1985: pollen), Bouman and Meijer (1986: seeds, 1994: ovules and seeds), Meijer (1993: general), Nais (2001: general, superb photographs), the Parasitic Plants website (Nickrent 1998 onwards: general) and also Heide-Jørgensen (2008: general).

Previous Relationships. Rafflesiales of some authors included a number of echlorophyllous, parasitic groups including Cytinaceae (here Malvales), Apodanthaceae (Cucurbitales), Mitrastemonaceae (Ericales) and of course Rafflesiaceae. Many early and more recent authors have sought an affinity between Rafflesiaceae and taxa like Aristolochiacaeae (references in Takhtajan 1997), perhaps in part because of a belief that the pollen of the former had only a single aperture, as did that of Aristolochiaceae; there is a gynostemium of sorts and extrorse anthers in both. Cocucci and Cocucci (1996) saw connections of Rafflesiaceae first with Apodanthaceae and then with Annonaceae.

EUPHORBIACEAE Jussieu, nom. cons.   Back to Malpighiales

Herbs to trees (lianes), commonly laticiferous; (plants Al-accumulators); cucurbitacins [triterpenes], ellagitannins [geraniin and mallotussic acid], lectins [hemagglutinins], cocarcinogens [phorbol ester diterpenes] +; cork also outer cortical (pericyclic); vessel elements often in multiples, (with scalariform perforation plates); (pits vestured); sieve tubes with non-dispersive protein bodies; (nodes also 1:1 [?Actinostemon] or 5 or more:5 or more); petiole anatomy very variable, often ± annular, etc.; stomata various; leaves spiral, two-ranked or opposite (palmately compound), vernation variable, margins entire or single veins running into opaque persistent tooth, 2ndary veins palmate (pinnate), subbasal glands +/0, petioles often apically pulvinate, (stipules 0); plant monoecious or dioecious; K (2-)3-6(-12), (connate), C ?0, disc +; staminate flowers: A 1-many, (connate), extrorse or introrse, pollen bi- or trinuclear, pistillode 0; carpellate flowers: staminodes 0; G [(2) 3(-many)], (alt. with 3 P - Excoecaria), median member usu. abaxial, micropyle exo(bi)stomal, nucellus often projecting beyond micropyle, placental obturator +, style (short), branched or not, stigmas prominent, often branched or with adaxial furrow, dry or wet; valves of fruit falling off, (fruit indehiscent; aril +); (seed pachychalazal), exotegmen palisade [lignified Malpighian cells]; endosperm + (0), embryo green or white; n = (5-)9(-11+).

218[list]/5735 - four groups below. Pantropical, also (warm) temperate (map: see Meusel et al. 1978, Canada approximate). [Photo - Flower, Flower, Fruit, Fruit.]

1. Cheilosioideae K. Wurdack & Petra Hoffmann

A 5-12, pollen echinate, (G [2]), outer integument 8-10 cells across, inner integument 8-12 cells across; seeds not carunculate; testa with vascular bundles; endosperm.

2/7. Burma, Malesia (map: from van Welzen 1994).

Van Welzen (1994) described Neoscortechinia as having a thin, red aril, but no aril was mentioned by Tokuoka and Tobe (2003) or Tokuoka (2007).

Acalyphoideae [Crotonoideae + Euphorbioideae]: (phorbol esters [diterpenes] +); outer integument 6-10 cells or so across.

2. Acalyphoideae Beilschmied s. str.

Outer integument 3-6(-16) cells across, inner integument 3-24 cells across; (testa with vascular bundles).

Acalypha (430: stigmas much branched), Macaranga (240; some ant plants, see Bänfer et al. 2006 for a phylogeny), Tragia (170), Mallotus (140), Dalechampia (115: pseudanthia), Claoxylon (80). Pantropical.

Synonymy: Acalyphaceae J. Agardh, Mercurialaceae Martynov, Treviaceae Lindley.

Crotonoideae + Euphorbioideae: laticifers +.

There is great variation in the phorbol esters found in this group.

See Rudall (1987, 1994) for laticifers, and the cautionary comments in Wurdack et al. (2005).

3. Crotonoideae Beilschmied

Hairs often stellate or lepidote; laticifers articulated or not; cyanogenesis via the valine/isoleucine pathway; (lamina abaxially with paired pale glands near the petiole junction); petals +/0, pollen inaperturate and with supractectal processes, colpate, or porate; seeds carunculate/arillate or not, often pachychalazal; (exotesta palisade, endotestal cells ± palisade, thin-walled, slightly lignified), tegmen usu. with vascular bundles; (100+ bp deletion in trnL-F spacer).

Croton (1300), Jatropha (175), Manihot (100), Trigonostemon (95), Cnidosculus (75). Pantropical, also temperate.

Synonymy: Crotonaceae J. Agardh

4. Euphorbioideae Beilschmied

Laticifers not articulated, starch grains much elaborated?; staminate flowers: A not covered by P, disc usu. 0; outer integument 3-6 or 8-22 cells across, inner integument 3-5(-22) cells across; seeds carunculate or not.

Euphorbia (2420, inc. Chamaesyce, Pedilanthus, Monadenium, Synadenium, etc.), Mabea (40). Pantropical, extending (mostly Euphorbia) into temperate regions.

Synonymy: Bertyaceae J. Agardh, Hippomanaceae J. Agardh, Ricinaceae Martynov, Ricinocarpaceae Hurusawa, Tithymalaceae Ventenat, Tragiaceae Rafinesque

• Euphorbiaceae may be recognised by the leaves on the one branch often being variable in size and/or shape, their secondary veins are often ± palmate, the margins are toothed, and there are sometimes glands of various kinds. Cauline stipules are common, as is latex (the latter not in Acalyphoideae). The plants are mono- or dioecious, the flowers are small, the perianth usually inconspicuous, there are usually three carpels with prominent stigmas, and the fruits have a distinctive and persistent columella, large and often carunculate seeds (one per loculus), and explosive dehiscence. Euphorbiaceae are quite often poisonous.

Evolution. Divergence & Distribution. Euphorbiaceae may have diverged from other Malpighiales in the Cretaceous-late Aptian ([119.4-]113.8[-110.7]/[105.9-]101.6[-101.1] million years before present), but diverficiation within the family is much more recent, for instance, that within Acalyphoideae occurred within the last ca 70 million years (Davis et al. 2005a). Divergence within Euphorbieae may have begun (63.5-)48.9(-40.5) million years ago (Bruyns et al. 2011, q.v. for other dates within Euphorbieae). A Mallotus-Macaranga-like plant has been found in deposits from New Zealand that are about 23 million years old - this clade is not currently known from the islands (Lee et al. 2010).

"Euphorbiaceae", i.e. including Phyllanthaceae, Putranjivaceae, etc., are often the second most abundant family in tropical rainforests in South-East Asia and Africa (Gentry 1988).

Plant-Animal Interactions. Caterpillars of nymphalid butterflies are quite common on Euphorbiaceae (Ehrlich & Raven 1964), e.g. caterpillars of the ca 340 species of Biblidinae are found on Dalechampia and Tragia (DeVries 1987; Wahlberg et al. 2009). Caterpillars of the spectacular Uraniinae moths can be found on Endospermum, Omphalea and Suregada throughout the tropics (Lees & Smith 1991); the first two are rather closely related, the position of the last is unclear (Wurdack et al. 2005). It would be interesting in this context to clarify both Euphorbiaceae phylogeny and Uraniinae host plant preferences.

In Malesia about 29 species of fast-growing, large-leaved Macaranga are the ecological analogues of the New World Cecropia (Urticaceae). Food bodies (Beccarian bodies) and extra-floral nectaries provide food for the ants (Crematogaster spp.), which live in obligate association with the plants in their hollow stems which are either hollowed out by the ant or become hollow as the stem ages; mymecophytism seems to have evolved more than once in the genus (Hatada et al. 2001 for references; Feldhaar 2003a, b). The association with the ants is some 20-16 million years. Coccus scale insects provide carbohydrates for the ants, but that association is only 9-7 million years old (Ueda et al. 2008). Other members of this association include Arhopala (a lycaenid) caterpillars which are not attacked by the ants, rather, the products of a tentacle-like gland that is extruded by the caterpillar calm the ants (Maschwitz et al. 1984). Pollination by thrips (Thysanoptera) seems to be particularly common in myrmecophytic species of Macaranga (Fiala et al. 2011); 24/29 species may be so pollinated, based on floral morphology, about double the frequency when compared with non-myrmecophytic species of the genus growing in the West Malesian localities that Fiala et al. visited.

Bacterial/Fungal Associations. Complex maytansinoids, ansamycin antibiotics, that are likely to be synthesized by fungal endophytes or other plant associates, are found in Trewia (Cassady et al. 2004 for references). The fungus Uromyces pisi causes Euphorbia cyparissias to form nectar-producing pseudoflowers that facilitate transmission of the fungus spermatia (Pfunder & Roy 2000).

Floral Biology & Seed Dispersal. Flowers of Euphorbiaceae are generally small, and pseudanthia have originated more than once (and also in Peraceae). However, there seems to be but a single origin of the distinctive cyathium of Euphorbia (Park & Backlund 2002; Wurdack et al. 2005), and although this characterises a very species-rich clade, the development of the diversity in Euphorbia may also be associated with the evolution of a variety of distinctive life forms (Horn et al. 2009a) and seed dispersal types and the adoption of C₄ photosynthesis (see below). It has been suggested that the distinctive cyathial nectariferous glands are commissural stipules (Steinmann & Porter 2002), while the cyathium seems to be a modified cymose inflorescence with a single, terminal, carpellate flower (cf. Jatropha, etc.); details of its development are provided by Prenner and Rudall (2007), although they found that the morphological nature of both cyathial glands and the petaloid structures surrounding the "flowers" was unclear (see also Hoppe 1985 and Prenner et al. 2008b). Indeed, at the level of gene expression, "floral" genes may be expressed in the cyathium as a whole (Prenner et al. 2011). The evolution of the distinctive red, spurred, monosymmetric cyathia in New World species of Euphorbia that used to be segregated as Pedilanthus (bird pollination occurs here) has been studied from the point of view of whether or not they represent a "key innovation" (Cacho et al. 2010): The jury is out, but there aren't many species in this clade... Dalechampia of the Acalyphoideae also has remarkable pseudanthia of a different kind; here bees may visit the "flowers" for resin, a very uncommon reward in flowering plants (see Armbruster 1996 for details), although the resin has secondarily become used for defence in some species, probably its original fuction (Armbruster et al. 2009).

Seed dispersal is initially usually by the explosion of the capsule, the seed being hurled quite some distance - to 45 m in Hura crepitans, the sand-box tree (Swaine & Beer 1976). The seeds especially of Euphorbia may have nutritive arils or caruncles (e.g. Rössler 1943) which facilitate further local dispersal of the seeds, especially by ants; a total of ca 2300 species in the family, many in Euphorbia, are likely to be myrmecochorous (Lengyel et al. 2010). In Euphorbia subgenus Chamaesyce section Anisophyllum a number of species have testas that become mucilaginous when wetted (Jordan & Hayden 1992).

Ecology & Physiology. Both growth patterns and carbon fixation pathways show much diversity. Euphorbia s. str. (i.e. not including Chamaesyce, etc.) alone being extremely variable (Keller 1996), but with the inclusion of Chamaesyce and other segregate genera (e.g. Horn et al. 2009) there is yet more diversity. Basic relationships in the genus are [Esula [Rhizanthium [Euphorbia + Chamaesyce]]] (subgeneric names, see Bruyns et al. 2011, also below).

Both the cactiform life form and the annual habit, the latter in subgenera Chamaesyce and Esula, seem to be associated with much speciation (Horn et al. 2009, 2010b), and the annual habit has evolved eight times or more in subgenus Esula alone (Frajman & Schönswetter 2011). Some of the growth forms are decidedly odd, thus E. alata has spirally two-ranked leaves. Some species of Euphorbia are quite massive stem succulents and are cactus-analogues of drier areas throughout Africa and into India and even beyond (Steinmann & Porter 2002; Bruyns et al. 2006, 2011). Such species are a particularly prominent component of the winter rainfall vegetation of the Succulent Karoo of south west Africa (Nyffeler & Eggli 2010b). Succulence has evolved in some 800 species belonging to all four subgenera, but subgenera Rhizanthium and Euphorbia are made up mostly of succulent species, and they lack any annuals (Bruyns et al. 2011; Morawetz & Riina 2011). Succulence is of various types. The plants may have variously articulated or simply pencil-like stems, the latter as in some species of subgenus Chamaesyce, or they may be medusoid, with relatively slender but succulent branches radiating from a stout central axis, and they may be spiny (in subgenus Euphorbia there are spine shields; there are also stipular spines and spines in the stipular position, but not actually vascularized) or thorny (see e.g. Park & Jansen 2007; Carter 2002, esp. illustrations; Bruyns 2010). Bruyns et al. (2011) describe the different forms of stem succulence found in the genus in detail, and they note that in a number of species of subgenus Euphorbia the branches become permanently differentiated; orthotropic axes will not develop from branches. Bruyns et al. (2011) also date divergences in the genus; those within the largely succulent subgenera Rhizanthium and Euphorbia began somewhat less than 30 million years ago, (38.2-(28.1(-22) and (39.6-)29.9(-22.5) million years respectively, with much speciation in the latter subgenuus in particular occuring within the last ca 13 million years.

Given the prevalence of succulence in Euphorbia, it is not surprising that crassulacean acid metabolism is quite common in the genus. It has evolved ten times or so, especially notable cases being in subgenera Rhizanthium and Euphorbia, the two subgenera in which the succulent habit is particularly common (Horn et al. 2010b; Bruyns et al. 2011). Most of the ca 300 species of subgenus Chamaesyce section Anisophyllum have C₄ photosynthesis, but C₃ and CAM photosynthesis also occur in the subgenus (Yang & Berry 2011a). The C₄ clade probably evolved in drier areas of North America, and it is sister to a clade with C₄/C₃ intermediates (Yang & Berry 2011a, esp. b). Maximum estimates of the age of origin of the pathway in Euphorbia are (13.1-)10.4(-7.3) million years (Christin et al. 2011b). Some C₄ species grow in the more arid parts of Africa and are also succulents. Species of section Anisophyllum growing on Hawaii form a distinctive woody radiation and include some of the largest C₄ plants anywhere, being trees up to 9 m tall growing in mesic forests (Pearcy & Troughton 1975). They appear to have evolved from within a small clade of weedy annuals now found in Southern USA, Mexico, and the Caribbean (see also Yang et al. 2009); hybridisation is involved in their origin, and this occurs elsewhere in the C₄ clade (Yang & Berry 2011b). Note that the whole plant body of some species in section Anisophyllum can perhaps be compared with the branching pattern of the inflorescence of other species of Euphorbia; the seedling apex aborts after the production of a single pair of leaves, and several axillary shoots with complex determinate branching produce the adult plant (Hayden 1988). There is a great diversity of starch grain morphologies in the latex of species in this clade (Biesboer & Mahlberg 1981).

Chemistry, Morphology, etc. There is great diversity in phorbol esters in the [Crotonoideae + Euphorbioideae] clade. Cyanogens in Euphorbiaceae s. str. can be derived from nicotinic acid or valine/isoleucine (Seigler 1994); latex and cocarcinogens are both apparently restricted to Euphorbioideae and Crotonoideae. Distinctive fatty acids in the seed oils are quite common here (Badami & Patil 1981); for lectins, see Vandenborre et al. (2011).

See Rudall (1987, 1994) and Wiedenhoft et al. (2009) for laticifers in Euphorbiaceae, also the cautionary comments in Wurdack et al. (2005). Biesboer and Mahlberg (1981) describe the complex morphology of the starch grains found in the latex of Euphorbia and laticifer evolution there. Claoxylon has distinctively rough leaves when dry because of the styloids in their tissues (Kabouw et al. 2008). Prismatic crystals in wood parenchyma and/or ray cells are common, and these also occur in Putranjivaceae and Picrodendraceae (Hayden 1994).

Prenner et al. (2008a) described the development of the distinctive androecium of Ricinus with its branched stamens which, however, are not cauline as has sometimes been suggested. Mennega (1990) suggested that the subdermal initiation of the inner integument separated Euphorbiaceae from other families. Some Euphorbiaceae are reported to have two vascular traces supplying each ovule (Venkata Rao & Ramalkshmi 1967). Johri and Kapil (1953) describe the vascular tissue in Acalypha indica as proceeding one third the way up the nucellus. The projecting nucellus in Codiaeum variegatum, at least, seems to result from periclinal divisions of the epidermal layer of the nucellus, the nucellar cap, although in Euphorbia less striking projections seem to be the result of divisions of the underlying nucellar cells (Bor & Kapil 1975 and references).

For general information on Euphorbiaceae, also Phyllanthaceae, Putranjivaceae, etc., see Webster (1967, 1994a - also other papers in Ann. Missouri Bot. Gard. 81. 1994: general), Hegnauer (1966, 1989: chemistry), Hans (1973: chromosomes), Evans and Taylor (1983: phorbol esters), Jury et al. (1987: chemistry), Beutler et al. (1989, 1996: chemistry), Kapil (1960: embryology), Tokuoka and Tobe (1993: general embryology, 1998: ovules and seeds in Crotonoideae, 2002: ovules and seeds in Euphorbioideae, 2003: ovules and seeds in Acalyphoideae), Bor & Bouman (1975: ovules and seeds in Euphorbioideae), Merino Sutter and Endress (1995: floral morphology), De-Paula and Sajo (2011: anthers and ovules in Croton), Singh (1969), and Stuppy (1996), all seed anatomy, Hayden and Hayden (2000: wood anatomy of Acalyphoideae), Lobreau-Callen et al. (2000: pollen, esp. of Crotonoideae), Radcliffe-Smith and Esser (2001: morphology of genera), Esser (2001: general), Westra and Koek-Noorman (2004: wood end-grain), Mennega (2005: wood anatomy of Euphorbioideae), Tokuoka (2007: character evolution), Cervantes et al. (2009: leaf anatomy of some Acalyphoideae). For pollen morphology of Acalyphoideae s.l., see Nowicke and Takahashi (2002) and references, for that of Acalypha, see Sagun et al. (2006), and for that of Plukenetieae and Euphorbieae, see Suárez-Cerbera et al. (2001).

Phylogeny. Molecular analyses by Wurdack and Chase (2002) and especially Wurdack et al. (2005, see also Tokuoka 2007) suggest that substantial changes may be needed in the groupings currently recognised in the family. The beginning of the reclassification they suggest is given here, with the interpolation of Rafflesiaceae as suggested by Davis et al. (2007) and the associated recognition of Peraceae; the main problem remaining is the circumscription of Crotonoideae.

Suregada (Crotonoideae) is pantoporate, and its pollen also lacks columellae; it is in the C₁ clade. Indeed, although there are number of distinctive features in the Crotonoideae as broadly construed, there is no evidence that it is monophyletic (see the C_1-5 clades in the tree, the C_1-2 clades are the same as in Wurdack et al. 2005), and many of the characters in the subfamilial characterization above are synapomorphies either for individual clades or groups within them (the latter the trnL-F spacer deletion - a feature of part of Crotonoideae s. str.). Crotonoideae s. str., the C_1-2 clades (Crotonoideae may expand from this minimalist circumscription as details of phylogenetic relationships are clarified), for the most part have petals, distinctive inaperturate pollen with supratectal processes, and the tegmen is usually vascularized. The large genus Croton is being actively studied by Berry and collaborators (see Berry et al. 2005; van Ee et al. 2008, 2011; van Ee & Berry 2009; Riina et al. 2009, 2010; Caruzo et al. 2011 for phylogenies, biogeography, and more). Croton and immediate relatives can be quite readily recognised: Some leaves turn orange with age, the indumentum is stellate-lepidote, there are distinctive often yellowish glands on the petiole, and the stamens are inflexed in bud.

Although Acalyphoideae in the old sense is paraphyletic, the great bulk of the subfamily is included in a single, strongly-supported clade, Acalyphoideae s. str. The plesiomorphic thickness of the outer integument may be 6-10 or so cells across, but Tokuoka (2007) noted that Adenoclineae and Gelonieae have a thinner outer integument, and they may form a paraphyletc grade at the base of this big clade, albeit with very little support. Slik et al. (2001: morphology), Sierra et al. (2006, 2010 and references [the latter with symmetric resampling values and both qualitative and quantitative variation used]) and Kulju et al. (2007a, b) evaluate the phylogeny of the Macaranga-Mallotus complex; there are three main clades, and in Mallotus s. str. in particular some small, segregate genera are embedded.

For a phylogeny of Euphorbia, see Molero et al. (2002: Macaronesian taxa), Bruyns et al. (2006), Park and Jansen (2007), Zimmermann et al. (2010) and Wurdack et al. (2011). The last three authors found that subgenus Esula was sister to The Rest, although not always with very strong support - relationships are [Esula [Rhizanthium [Euphorbia + Chamaesyce]]], and the same relationshiops were found in the extensive study by Bruyns et al. (2011). The genus is very large, so sampling was initially poor, however, sampling is steadily improving. For relationships in subgenus Esula, see Frajman and Schönswetter (2011: position of E. lathyris unclear; also summary in Geltman et al. 2011), for those in Rhizanthium, in which the only Malagasy species, E. antso, is sister to the rest, see Morawetz and Riina (2011), in the mostly New World subgenus Chamaesyce, see Yang and Berry (2007, 2011), for those in subgenus Euphorbia, see Dorsey et al. (2011: also growth form evolution), and for the evolution of succulence in all four subgenera, see Bruyns et al. (2011); see also above for succulence, spinyness, and photosynthetic pathways in the clade.

Classification. For a comprehensive checklist and bibliography of the family, see Govaerts et al. (2000), while Radcliffe-Smith and Esser (2001) describe the genera. For an outline of the classification of the speciose Macaranga, seee Whitmore (2008). For information on Euphorbia, see the developing site http://www.euphorbiaceae.org - Euphorbia (Esser et al. 2009); Euphorbia is best broadly circumscribed, so including the whole of the Euphorbiinae of Webster (1994b) and being characterized by the possession of a cyathium (e.g. Bruyns 2010 and references). For generic limits in the Macaranga-Mallotus area, see Kulju et al. (2007a) and Sierra et al. (2007), and for a sectional classification of Croton, see van Ee et al. (2011).

Previous Relationships. Cronquist's Euphorbiales included Simmondsiaceae (Caryophyllales), Pandaceae (Malpighiales) and Buxaceae (Buxales), whilst Takhtajan's (1997) Euphorbianae included Pandaceae and Dichapetalaceae (Malpighiales), as well as Thymelaeales (now in Malvales) and Aextoxicaceae (Berberidopsidales), but these are clearly groups that have little to recommend them.

Merino Sutter and Endress (1995) argue for a rather broadly delimited Euphorbiaceae (inc. both Phyllanthaceae and Putranjivaceae), Huber (1991) for a narrower circumscription, with the biovulate taxa (Phyllanthaceae, Picrodendraceae, Putranjivaceae) being considered to be closer to Linales s. str., while Meeuse (1990) also suggested that the family should be split - into eleven families. There is no molecular evidence yet for a broadly delimited Euphorbiaceae (unless Linaceae et al. are to be included), yet Euphorbiaceae s. str, Phyllanthaceae and Picrodendraceae all have a similar and rather distinctive capsule, etc. (see also Merino Sutter et al. 2006).

Botanical Trivia. Croton has got nothing to do with the cultivated croton, which is Codiaeum.

Thanks. I am grateful to Hajo Esser for comments.

[Phyllanthaceae + Picrodendraceae]: stomata paracytic; plant monoecious; flowers small; style +; micropyle bistomal, parietal tissue 10 or more cells across, obturator and nucellar beak +; fruit walls also splitting from the persistent columella, mesocarp often separating from endocarp; x = 13.

Evolution. Divergence & Distribution. Phyllanthaceae and Picrodendraceae may have diverged in the Cretaceous-Albian 111-100 million years before present ([114.0-]108.1[-105.8]/[101.9-]97.1[-95.6] million years before present: Davis et al. 2005a).

Merino Sutter et al. (2006) suggest possible similarities between the two other than those mentioned above.

Chemistry, Morphology, etc. For chemistry, see Hegnauer (1966, 1989, as Euphorbiaceae) and Jury et al. (1987), see also Webster (1994a, b: general), Radcliffe-Smith and Esser (2001: description of genera), and Wurdack et al. (2004: phylogeny and morphology).

Phylogeny. The clade [Phyllanthaceae + Picrodendraceae] has only very slight support in a rbcL analysis. However, there are morphological similarities (Wurdack et al. 2004: two ovules/carpel, etc.), and the support is stronger (75% bootstrap, 1.0 posterior probablility) in a recent 4-gene analysis (Davis et al. 2005a; see also Tokuoka & Tobe 2006; Korotkova et al. 2009) and even stronger in Soltis et al. (2011). Thus the two groups are probably sister taxa.

PHYLLANTHACEAE Martynov   Back to Malpighiales

Herbs to trees; (plants Al accumulators); cyanogenesis via the tyrosine pathway, tropane and pyrrolizidine alkaloids, cucurbitacins [triterpenes], nonhydrolysable tannins [geraniin] +, ellagic acid 0; cork?; vessel elements with simple [Glochidion] or scalariform [Aporosa] perforation plates; (axial parenchyma 0); (nodes 1:1); (mucilage cells [epidermis] +); (stomata anisocytic); leaves on orthotropic axes often reduced, spiral, on plagiotropic axes two-ranked (spiral), involute or conduplicate, margins entire (toothed); (plant dioecious); K 2-8(-12), often basally connate, C (0, 3-)5(-9), (small); disc variously lobed, extrastaminal (0, central); staminate flowers: A 2-35, often ± connate, extrorse, pollen reticulate, (pistillode +); carpellate flowers: (staminodes +); G 1 [2-5(-15)], styles usu. bifid, stigmas with adaxial furrow, wet; outer integument 2-many cells across, inner integument 2-3(-10) cells across, parietal tissue protruding through micropyle, placental obturator +; fruit a septicidal capsule/schizocarp; seeds large, (caruncle +); (vascular bundles in testa), tegmen 2-5(-20) cells thick, exotegmen with (radially-elongated) ribbon-like cells; endosperm copious (0); n = (6-9, 11, 14).

59[list]/1745. Pantropical, but esp. Malesia, some temperate (map: from Webster 1970, 1984, etc.; FloraBase 1.2011 in part - not yet v. accurate...). Two subfamilies below. [Photo - Flower.]

1. Phyllanthoideae Beilschmied

Growth continuous; plant monoecious/dioecious; inflorescence fasciculate; (pollen to 16-colporate; colpi diploporate); G [2-6(-15)]; (ovules hemitropous); (fruit indehiscent).

38/ : Phyllanthus (1270), Cleistanthus (140), Bridelia (50). Tropical to Temperate.

Synonymy: Porantheraceae Hurusawa

2. Antidesmatoideae Hurusawa

Plant tanniniferous; (pits vestured - Bridelieae); growth rythmic; (sieve tubes with non-dispersive protein bodies - Bischofia); (petiole pulvinate; leaves trifoliolate, spiral, teeth deciduous - Bischofia); plant often dioecious; C often 0; G [1-5], (stigma plumose); fruit often indehiscent.

21/ : Antidesma (100), Aporosa (90), Uapaca (60), Baccaurea (50). Tropics and subtropics.

Synonymy: Antidesmataceae Loudon, Aporosaceae Planchon, Bischofiaceae Airy Shaw (tapetal cells 2-5-nuclear), Hymenocardiaceae Airy Shaw, Scepaceae Lindley, Stilaginaceae C. Agardh, Uapacaceae Airy Shaw

• Phyllanthaceae have a variety of growth forms, but can be recognised by their often finely-cracking bark, absence of latex, and leaves that are often two-ranked, entire, stipulate, pinnately-veined and usually lack glands. Monoecy is widespread, the flowers are small, and the explosively dehiscent fruit have a persistent columella; there are two ovules/seeds in each carpel.

Evolution. Divergence & Distribution. Lachnostylis, a small Cape genus, seems to be a relict element there, being dated to as much as 97 million years before present (Warren & Hawkins 2006), while Haegens (2000) discusses the distribution of the Baccaurea group as being initially the result of drift events occuring ca 80 million years ago. These ages should be re-examined For the (post-)Miocene E->W dispersal of Bridelia across the Indian ocean, see Li et al. (2009).

Bacterial/Fungal Associations. Species of the Madagascan Uapaca are ectomycorrhizal (Ducousso et al. 2008) and can locally dominate the vegetation.

Floral Biology. In a clade of some 500+ species of Breynia, Phyllanthus and Glochidion there is evidence of at least two different kinds of pollination mutualisms involving the moth genus Epicephala (Gracillariidae: Kato et al. 2003; Kawakita & Kato 2004a, b, 2006; Kawakita et al. 2004); the plants involved are all part of Phyllanthus s.l. (see below). These mutualisms seem to have evolved both more than once and also some time after the divergence of the clade in which they are found - 55.2-33.4 million years ago versus 35-20 million years ago - and they have also been lost (Kawakita & Kato 2009; Kawakita 2010).

Vegetative Variation. Phyllanthoid branching occurs in many, but not all, species of Phyllanthus s.l. (Kathriarachchi et al. 2006). The orthotropic axes have reduced, spirally-arranged leaves and the plagiotropic axes usually have two-ranked, photosynthetic leaves and flowers in the axils of those leaves; the latter axes are of more or less limited growth. The plagiotropic lateral branches of P. acidus may be short-lived and lack flowers, so being the functional equivalent of compound leaves; the flowers themselves are borne on short branches lacking photosynthetic leaves and which arise from separate axillary buds. Some Caribbean species are yet more modified. Thus the plagiotropic lateral branches of P. epiphyllanthus are cladodes and bear flowers and fruits in the axils of scale leaves on either side of the cladode.

Chemistry, Morphology, etc. The only record of cocarcinogens is from one species of Antidesma (Beuteler et al. 1989). Wood anatomy is variable (Hayden & Brandt 1984) and the nodes may quite commonly be unilacunar (Thakur & Patil 2002). The inflorescence of Uapaca is a pseudanthium. The pollen is very variable in Phyllanthus in particular (Webster 1956). The outer integument is variable in thickness. The fruit type of the ancestor of Phyllanthaceae is unclear (Kathriarachchi et al. 2005). The exotegmen is most often described as being ribbon-like or tracheoidal. However, Hymenocardieae (Didymocistus, Hymenocardium) have a collapsed tracheoidal exotegmen and large tanniniferous endotegmic cells; do they belong here (Tokuoka & Tobe 2001)? - yes, say Wurdack et al. (2004) and Kathriarachchi et al. (2005).

For additional information, see also Köhler (1965: pollen), Hans (1973: chromosomes), Levin (1986: leaves), Mennega (1987: wood anatomy), Tokuoka and Tobe (2001: ovules and seeds), Sagun and van der Ham (2003: pollen morphology of Flueggeinae), Westra and Koek-Noorman (2004: wood end-grain), Webster and Carpenter (2008: pollen of Phyllanthus et al.), León Enriquez et al. (2008: architectural variation in the family), Chen et al. (2009: pollen of Phyllanthus), and Sagun and van der Ham (2009: pollen of Phyllanthoideae-Flueggeinae).

Phylogeny. Phyllanthaceae include most of the old Euphorbiaceae-Phyllanthoideae, minus Drypetes and relatives, for which see Putranjivaceae. They divide into two main clades, one largely with fasciculate inflorescences (it includes Lingelsheimia, sometimes associated with Putranjivaceae, and Dicoelia, linked to Pandaceae), Phyllanthoideae above, and the other (including Hymenocardieae) tanniniferous, Antidesmatoideae above (Kathriarachchi et al. 2005, a five-gene analysis; Hoffmann et al. 2006). For the phylogeny of Phyllanthus, see (Kathriarachchi et al. 2006; Pruesapan et al. 2008). For phylogenetic relationships, see also Wurdack et al. (2004), morphology also discussed, and the odd genus Croizatia was included, and Samuel et al. (2005: two gene analysis), while Voronstova et al. (2007) studied the phylogeny of Poranthereae. Hoffmann et al. (2006) provide the phylogenetic classification followed here.

Classification. Govaerts et al. (2000: as Euphorbiaceae) provide a checklist and bibliography, but this is now dated - e.g. see Vorontsova and Hoffmann (2008) for genera in Phyllanthoideae-Poranthereae.

The limits of Cleistanthus will have to be adjusted, and most species will need a new name (Li et al. 2009), while the large genus Phyllanthus is paraphyletic, and its limits should probably be broadened to include Glochidion (some 300 species), Breynia, Sauropus (70 spp.), etc. (Kathriarachchi et al. 2006; Lorence & Wagner 2011 - but cf. Pruesapan et al. 2008). For a monograph of Baccaurea and relatives, see Haegens (2000) and of Aporosa, see Schot (2004).

PICRODENDRACEAE Small, nom. cons.   Back to Malpighiales

Picrotoxanes +, otherwise chemistry?; cork?; vessel elements with simple perforation plates; ?nodes; mucilage cells [epidermis] + (0); subsidiary cells piggy back [on top of guard cells]; hairs unicellular or unbranched uniseriate; leaves spiral, opposite, (two-ranked), 2ndary venation ± palmate or leaves palmate, margin toothed [teeth with deciduous apex] or entire, stipules petiolar, cauline, with axillary colleters, or 0; plant dioecious); disc central or interstaminal; staminate flowers: P 3(-13); A 2-many, (connate basally), often extrorse; nectary between or inside A; pollen 4-brevicolporate, 5-6-porate, zoni- or pantoaperturate, echinate to verrucose; pistillode +/0; carpellate flowers: P (3-)4-8(-13); G (2-)3(-5), stigmas stout, entire (multifid), dry (wet); (micropyle endostomal - Austrobuxus), outer integument 5-6 across, inner integument 3-6 cells across, nucellar cap +, (nucellar beak +), hypostase +, funicular obturator +, with hairs; (fruit indehiscent); seeds carunculate (0), vascular bundle branching in chalaza; exotegmen cuboid or fibrous, [palisade, subprocumbent, mesotegmen ± thickened, endotegmen 2-layered, with banded thickenings- Oldfieldia]; endosperm + (0), (ruminate - Picrodendron), embryo green, cotyledons broader than radicle (plicate; lobed - Picrodendron); (n = 12 - Pseudanthus).

24[list]/80 - three groups below. Many small genera; tropical, esp. New Guinea - Australia - New Caledonia or America plus Africa - Madagascar (map: from Webster 1994; van Welzen & Forster 2011; FloraBase i.2012 - incomplete). [Photo - Picrodendron Fruit © A. Gentry.]

1. Podocalyx

?

1/1. Podocalyx loranthoides. Amazonia.

[Caletieae + Picrodendreae]: seeds carunculate.

2. Caletieae

?

Largely Australasian, New Caledonia.

Synonymy: Androstachyaceae Airy Shaw, Micrantheaceae J. Agardh, Paivaeusaceae A. Meeuse, Pseudanthaceae Endlicher

3. Picrodendreae

?

Africa, America

• Picrodendraceae are vegetatively rather heterogeneous, although they often have opposite, toothed and stipulate leaves with pinnate venation and deciduous glands capping their teeth. The capsules are like those of Euphorbiaceae and the seeds may be carunculate.

Seed Dispersal. Myrmecochory may occur in the majority of the species of the family (Lengyel et al. 2009, 2010).

Chemistry, Morphology, etc. The family is poorly known. Picrodendron may have a perianth of two whorls (Hakki 1985), or perhaps it is modified quincuncial. Information is taken from Hayden (1977, 1994: wood anatomy), Levin and Simpson (1994: pollen), Huber (1991) and Tokuoka and Tobe (1999: seed anatomy), Wurdack et al. (2004: some morphology), Westra and Koek-Noorman (2004: wood end-grain), and Merino Sutter et al. (2006: morphology of carpellate flowers).

Phylogeny. For the taxa included in this family, see Euphorbiaceae-Oldfieldioideae Köhler & Webster (Webster 1994b). Paradrypetes is probably to be included in Rhizophoraceae, although agreeing with Podocalyx in particular in wood anatomy and in details of pollen morphology (Levin 1992). Croizatia (see Levin 1992) is also odd, with 5 petals, an extrastaminal disc and style with distinct styles, and it lacks the distinctive pollen of the family; it is here placed in Phyllanthaceae (confirmed by molecular data: see Wurdack et al. 2004; Wurdack 2008). Stuppy (1996) noted that both Picrodendron and Oldfieldia were rather different from other taxa included in his Oldfieldioideae, and he compared the latter with Meliaceae because of similarity in seed characters. However, both genera are firmly in Picrodendraceae-Picrodendreae.

Classification. Govaerts et al. (2000) provides a checklist and bibliography (as Euphorbiaceae).

Balanopaceae [[Trigoniaceae + Dichapetalaceae] [Chrysobalanaceae + Euphroniaceae]]: hairs simple [unicellular always?]; ovules collateral, micropyle bistomal, nucellus evanescent by maturity, endothelium +; endosperm at most slight.

Evolution. This clade may have diverged at the beginning of the Cretaceous-Albian 111-100 million years before present, Balanopaceae separating from the rest at the end of this period ([106.2-]99.6[-95.5]/[94.9-]90.2[-88.5] million years before present: Davis et al. 2005a).

Chemistry, Morphology, etc. For ovule position in the clade, see Merino Sutter and Endress (2003). Tobe and Raven (2011) suggest that there is a multiplicative inner integument. For a comparison of the floral morphology of the whole clade, see Matthews and Endress (2006a).

Phylogeny. For relationships, see especially Litt and Chase (1999).

[Balanopaceae [[Trigoniaceae + Dichapetalaceae] [Chrysobalanaceae + Euphroniaceae]]]: hairs simple [unicellular always?]; ovules collateral, micropyle bistomal, outer integument 5< cells across, inner integument 5< cells across, nucellus evanescent by maturity, endothelium +; endosperm at most slight.

Evolution. Divergence & Distribution. This clade may have diverged at the beginning of the Cretaceous-Albian 111-100 million years before present, Balanopaceae separating from the rest at the end of this period ([106.2-]99.6[-95.5]/[94.9-]90.2[-88.5] million years before present: Davis et al. 2005a).

Chemistry, Morphology, etc. For a comparison of floral morphology within the whole clade, see Matthews and Endress (2006a); for ovule position, see Merino Sutter and Endress (2003). Tobe and Raven (2011) suggested that there is a multiplicative inner integument; it is thick, but does not usually become thicker after fertilization; there is not enough information to consider that a vascularized testa is an apomorphy for the clade.

Phylogeny. For relationships, see especially Litt and Chase (1999); this group has held together strongly in subsequent studies.

BALANOPACEAE Bentham & J. D. Hooker, nom. cons.   Back to Malpighiales

Evergreen trees; ellagic acid?, prob. tanniniferous; vessel elements with scalariform perforations; parenchyma diffuse; sclereid nests with rhomboidal crystals in bark; petiole bundle?; bud scales +; cuticle waxes 0 (platelets); stomata usu. laterocytic; leaves spiral, tooth ?type, stipules minute; plant dioecious; staminate plant: inflorescence catkinate; P of small teeth; A (1-)3-6(-14), anthers much longer than filaments; pollen 3-5-colpate, exine columellate-granulate; pistillode common; carpellate plant: inflorescence a fascicle, bracts spirally arranged and forming cupule; P 0; G [(2)], styles long, once or twice bifid, stigmatic adaxially, ?type; ovules subbasal, apotropous but facing laterally, outer integument 5-7 cells across, inner integument 5-9 cells across, parietal tissue ca 2 cells across; fruit a drupe with 2-3 stones; testa vascularized, persistent, cell walls not much thickened; endosperm type?, slight, embryo green, large, cotyledons cordate; n = 20 (21); seedlings phanerocotylar, hypocotyl elongated.

1[list]/9. S.W. Pacific, especially New Caledonia (map: from van Steenis & van Balgooy 1966). [Photo - Habit]

• Balanopaceae look like a Myrica, but they lack its distinctive glandular hairs. The leaves are toothed, albeit sometimes minutely so, and are very coriaceous. The staminate flowers are in catkins, the carpellate flowers are single and surrounded by a cupule of spirally-arranged bracts; the flowers of both have no more than a rudimentary perianth. When dry, the cupulate, drupaceous fruits look somewhat like acorns; they have 2-3 stones.

Chemistry, Morphology, etc. The leaves are often described as being dimorphic (Carlquist 1980; Cronquist 1983), but they are no more so than in any plant that has bud scales. Cristarque cells occur in some species. Endress and Merino Sutter (2002) present details of the morphology of carpellate flowers; pollen descriptions in Feuer (1991) and Herendeen et al. (1995) differ somewhat. Batygina et al. (1991) provide details of testa anatomy, Merino Sutter and Endress (2003) of floral morphology, but overall little is known about mebryology.

Previous Relationships. Relationships of Balanopaceae have long been problematic. Cronquist (1983) compared their wood anatomy with that of Hamamelidaceae; Balanopales were included in Daphniphyllanae by Takhtajan (1997). Merino Sutter and Endress (2003) suggested that the floral morphology of Balanopaceae is closer to that of Euphorbiaceae than to other families of this group.

[[Trigoniaceae + Dichapetalaceae] [Chrysobalanaceae + Euphroniaceae]]: vessel elements with simple perforation plates; vestured pits +; mucilage cells +; stomata paracytic; lamina margins entire, (surface glands or glandular hairs +); pedicels articulated; flowers obliquely monosymmetric; K basally connate, with epidermal mucilage cells, quincuncial, 2 outer members shorter; fertile stamens abaxial, ± connate, anthers much shorter than filament, with a little pit where the filament joins, connective well developed abaxially with endothecium continuous there, staminodes adaxial; G with longitudinal furrows, unicellular unlignified hairs +, style +, stigma commissural; ovules [incompletely] tenuinucellate, micropyle zig-zag, outer integument 2-5 cells across, inner integument 3-8 cells across, obturator +.

Chemistry, Morphology, etc. Matthews and Endress (2008), which see for many more details, elaborate the floral morphology of this clade and suggest synapomorphies for its members.

Previous Relationships. Including these four families in Chrysobalanaceae s.l. was optional in A.P.G. II (2003), and specimens of Chrysobalanaceae and Dichapetalaceae are quite often misidentified as the other family (G. T. Prance, pers. comm.), however, the families are kept separate in A.P.G. III (2009).

[Trigoniaceae + Dichapetalaceae]: (vessel elements with scalariform perforations); petiole bundle arcuate; 2ndary veins strongly looping; inflorescences cymose; K with mesophyllar mucilage cells; nectary with lobes or scales, semi-annular [staminodial?]; ovary and lower style completely synascidiate; outer integument <5 cells across; testa multiplicative.

TRIGONIACEAE A. Jussieu, nom. cons.   Back to Malpighiales

Evergreen trees or lianes; helical thickening in ray and axial parenchyma; wood fluorescing [1 sp]; parenchyma in apotracheal bands; branched sclereids +; (split laterals +); hairs T-shaped, unicellular[?]; leaves opposite, spiral or two-ranked, dense whitish hairs below (not), stipules interpetiolar [when leaves opposite]; (inflorescence racemose - Isidodendron); C contorted, adaxial-lateral petal is the basally spurred or saccate standard, plicae in abaxial + abaxial-lateral petals form the keel, or these petals saccate; A 5-13, filaments ± connate, fertile stamens 4-9, staminodes 2-6; pollen 3-5-porate; nectary of 1 or 2 [and then each to 3-lobed] glands at base of standard (glands on base of staminodes - Isododendron); G [(4)], median member adaxial, placentation also parietal, stigma capitate to slightly trilobed; ovules 1-10/carpel, (crassinucellate), epitropous (apotropous), micropyle zig-zag, outer integument 2-3 cells across, inner integument 4-6 cells across, whole inner integument endothelial; fruit a septicidal capsule, carpels opening internally, central fibrous strands persisting, (hairs from endocarp- Trigoniastrum), or samara; seeds (winged); tegmen also multiplicative, exotesta with thickened outer walls, with long lignified hairs or not, endotegmic cells tanniniferous, walls slightly thickened; endosperm development?; embryo green [Trigonia], cotyledons large; n = ca 10; seedling phanerocotylar, hypocotyl elongated.

5[list]/28: Trigonia (24). Central and South America, Madagascar (Humbertiodendron), W. Malesia (Trigoniastrum) (map: from van Steenis 1949c; Lleras 1978). [Photo - Flower]

• Trigoniaceae are evergreen trees that may be recognised by their simple, entire, stipulate leaves that often have whitish indumentum below; dark glandular hairs or glands are common. The flowers are obliquely monosymmetric and are papilionaceous in their general appearance; the standard petal is more or less saccate or spurred.

Chemistry, Morphology, etc. Trigonia has opposite leaves, interpetiolar stipules, and split lateral vascular bundles; lamina glands are not obvious. The bracts of Trigoniastrum are more or less glandular, with large glands on the abaxial surfaces, Trigonia has stalked glands variously on pedicels or petioles and margins of bracts and leaves, while Humbertiodendron has concave marginal glands towards the base of the leaf blades.

For floral morphology, I follow the interpretations of Warming (1875) and Eichler (1878) rather than that of Cronquist (1981). Schnizlein (1843-1870: fam. 233) draws the flowers as being more or less vertically monosymmetric, while the orientation shown by Schatz (2001) is difficult to work out; in the latter it appears that the corolla may be quincuncial. Warming (1875) draws the nectary glands as being part of the androecial whorl; Lleras (1978) describes them as being "disc glands". In any event, the androecium at least sometimes seems to have more than 10 stamens. Testa anatomy is similar to that of Linaceae, where there is similar variation in ovules but the two are not immediately related.

Some information is taken from Lleras (1978), Takhtajan (2000), and Fernández-Alonso et al. (2000); see Hegnauer (1973) for chemistry.

Previous Relationships. Trigoniaceae were included in Vochysiales by Takhtajan (1997), while Cronquist (1981) placed the family in Polygalales.

DICHAPETALACEAE Baillon, nom. cons.   Back to Malpighiales

Evergreen trees, lianes; sieve tubes with non-dispersive protein bodies; parenchyma ± paratracheal; pericyclic sheath interrupted; fibres common; branching from current flush; hairs warty[?]; leaves spiral, (with flat abaxial glands), stipules fimbriate or not; inflorescence often epiphyllous, flowers small, (radial), (4-merous); C (connate; 3 small petals forming a "lip"), bifid (unlobed), drying black; nectary a ring, or lobes opposite petals; A = and opposite sepals, (3 + 2 staminodes; connate; adnate to C), (anthers without pits); pollen "small"; G [(2-4)] (inferior), (styles separate), stigmas ± punctate, wet, papillate; ovules ± apical, epitropous, outer integument 3-5 cells across, inner integument 6-8 cells across, hypostase 0, funicular obturator +; fruit a flattened drupe, 1(-3, then often lobed) locular; 1 seed/loculus; testa vascularized, only enlarged tanniniferous (divided) exotestal cells and remains of vascular bundles persist, exotegmen 0; embryo green or orange, oily; n = 10, 12.

3[list]/165: Dichapetalum (130: often very poisonous because of fluoracetic acid). Pantropical, few in Malesia (map: see Prance 1972b; Leenhouts 1957; van Steenis 1963; Heywood 1978 [Africa]). [Photo - Flower] [Photo - Fruit]

• Dichapetalaceae are trees or often lianes that may be recognised by their lenticillate twigs and stipulate (sometimes fimbriate-stipulate), often dark greyish-drying leaf blades with secondary veins that loop and join towards the margin (brochidiodromous venation); the venation is particularly prominent on the abaxial surface, where there are also often flat glands. The inflorescences are cymose and ± obviously epiphyllous, coming from the petiole; the small flowers have deeply bifid petals which dry blackish, and in Dichapetalum at least, the flowers fall off in their entirety if not fertilized leaving the prominent pedicels behind. The fruit is a drupe that is often flattened and/or lobed and is covered by short, dense, erect hairs which often give a shiny, almost golden appearance.

Chemistry, Morphology, etc. Dichapetalum at least has fluoracetic and related acids in its seed oils (e.g. Badami & Patil 1981). The petiole bundles are arcuate above the insertion of the inflorescence. The flowers of Tapura in particular are quite complex (Prance 1972b).

Some information is taken from Prance (1972b: general, inc. anatomy); see also Barth (1896) for petiole anatomy, Punt (1975) for pollen morphology, Hegnauer (1966, 1989) for chemistry, and Boesewinkel and Bouman (1980) for ovule and seed.

Previous Relationships. Dichapetalaceae were placed in Celastrales by Cronquist (1981) and in Euphorbiales by Takhtajan (1997).

Synonymy: Chailletiaceae R. Brown

[Chrysobalanaceae + Euphroniaceae]: hypanthium +, nectary on inside; C clawed, with lignified hairs.

Chemistry, Morphology, etc. Whether or not this clade has a spur in the floral cup is a matter of perspective; I prefer to interpret the flower in many Chrysobalanaceae as having the gynoecium "adnate" to one side of the hypanthium rather than being spurred as appears to be the case in a l.s. of the flower. Hairs have been found in the ovary loculi in flower, but there are not apparent in the capsule, even when unopened (pers. obs.).

CHRYSOBALANACEAE R. Brown, nom. cons.   Back to Malpighiales

Trees or shrubs; trihydroxyflavonoids, distinctive unsaturated fatty acids in the seeds +, ellagic acid 0; (cork ± deep-seated); true tracheids +; wood siliceous and with SiO₂ grains; parenchyma in apotracheal bands; nodes 5:5; petiole vasculature annular, often with medullary plates, etc., wing bundles +; branching from previous flush; (foliar sclereids +); leaves often two-ranked,  (flat-) conduplicate, (margins toothed), often with flat abaxial glands, esp. near base of lamina, (stipules petiolar or intrapetiolar); inflorescence various; (flowers almost polysymmetrical); (C 0); A (2-)5-many, usually long-exserted, abaxial members best developed, (connate); pollen also colpate, angled; usu. only abaxial carpel developed, (loculus divided; all three carpels fertile), often borne on side of tube, style ± gynobasic, stigma punctate (3-lobed); ovules ± basal, epitropous, outer integument 5-12 cells across, inner integument 5-12 cells across, micropyle bistomal (zig-zag); megaspore mother cells several, embryo sac lacking antipodals; fruit a 1-seeded drupe, often densely hairy inside, medium-sized to large; (seed ruminate), testa (multiplicative), vascularized, undistinguished or mesotestal, exotesta collapsed-fibrous, (tanniniferous), tegmen multiplicative; embryo large; n = 10, 11; germination cryptocotylar, hypogeal.

17[list]/460: Licania (170), Hirtella (105), Couepia (70), Parinari (45). Pantropical, especially American (map: from van Balgooy 1993; Prance & Sothers 2003a, b). [Photo - Flower]

• The family can be recognised by its strongly lenticillate twigs and two-ranked, often rather shortly petiolate and nearly always entire leaves; these either dry blackish grey and/or have well-developed scalariform tertiary venation. The stipules are long and early deciduous, there are often broad, flat glands on the abaxial surface of the lamina, and the petiole is more or less swollen at one or both ends. The wood is very hard and feels gritty when it is crumbled. The flowers have a hypanthium, there are often many long stamens, the style is more or less gynobasic, and the ovary is often borne on one side of the hypanthium. The one-seeded fruit is usually relatively large and the endocarp is often conspicuously hairy inside.

Evolution. Seed Dispersal. For seed dispersal, generally by animals, see Prance and Mori (1983).

Chemistry, Morphology, etc. Syllepsis is uncommon here (Keller 1994), but probably more generally in the whole group of five families.

For more information, see Morvillez (1918: petiole vasculature), Hegnauer (1973, 1990: chemistry), Badami and Patil (1981: seed fatty acids), Tobe and Raven (1984: embryology), Prance and White (1988: nicely illustrated variation in the family) and LaFrankie (2011: field characters).

Phylogeny. A recent molecular study (Yakandawala et al. 2010) yielded poor resolution of relationships, but suggested that groupings apparent in earlier morphological "taximetric" studies (Prance et al. 1969; Prance & White 1988) should be reexamined. There is some support for Atuna being sister to the rest of the family (see also Wurdack & Davis 2009).

Previous Relationships. The flowers of some Chrysobalanaceae look rather like those of Prunus, and Chrysobalanaceae and Rosaceae were often considered to be close (e.g. Cronquist 1981; Takhtajan 1997), either as separate families more or less adjacent in the sequence, or Chrysobalanaceae might even be included as a subfamily of Rosaceae. However, there are numerous differences between them (see table in Prance 1972a).

Classification. See Prance and White (1988: genera), Prance (1989: New World Taxa), and Prance and Sothers (2003a, b: world monograph).

Synonymy: Hirtellaceae Horaninow, Licaniaceae Martynov

EUPHRONIACEAE Marcano-Berti   Back to Malpighiales

Tree; parenchyma ± aliform-confluent; petiole bundles annular or arcuate, (not joining immediately with stele); cortical and foliar sclereids +; hypodermis mucilaginous; leaves spiral, revolute, white tomentose below; inflorescence terminal; C 3 [abaxial-lateral and abaxial C absent], contorted; stamens = and opposite sepals (4-7), in two groups, adnate to C, filaments basally connate, staminodes 1, long, abaxial-lateral, and 4-5 small and dentate; G with median carpel adaxial, stigma subcapitate; ovule apotropous; fruit a septicidal capsule, columella persisting; seeds winged, coat?; endosperm development?; n = ?

1[list]/1-3. The Guyana Shield, South America (map: from Steyermark 1987).

• Euphroniaceae are woody plants with entire, spiral, stipulate leaves the lower surfaces of which are covered with whitish indumentum; there are marginal abaxial glands near the base. The monosymmetric flowers are distinctive in having a short hypanthium and only three free petals; the fruit is a columellate, septicidal capsule and the seeds are winged.

Chemistry, Morphology, etc. Ovule morphology, etc., of Euphronia is still very poorly known. Lleras (1976) suggested that the (long) staminode of Euphronia was in the position of the fertile stamen of Vochysiaceae (that was a time when the two were believed to be related), Marcano-Berti (1995) that there is a staminal tube and four stamens of two different lengths. Some information is also taken from Warming (1875: general), Barth (1896: general anatomy), and de Pernia and ter Welle (1995: wood anatomy). Some more data come from Euphronia guianensis: Colonnello-Medina 712, vegetative anatomy.

Previous Relationships. Euphronia has been included in Trigoniaceae (Airy Shaw 1966; Hutchinson 1973; Takhtajan 1997) or Vochysiaceae (Cronquist 1981; Mabberley 1997). However, Euphroniaceae and Trigoniaceae differ in a number of features, including those of wood anatomy (see Lleras 1976 for a table) and other aspects of vegetative anatomy (e.g. Trigoniaceae lack the mucilaginous hypodermis of Euphronia: Sajo & Rudall 2002) and are not sister taxa.

CARYOCARACEAE Voigt, nom. cons.   Back to Malpighiales

Evergreen trees to shrubs; triterpenoid saponins + [Caryocar]; vessel elements with simple (scalariform) perforations; nodes 5 or more:5 or more; branched sclereids +; cuticle waxes as smooth to irregular platelets; colleters +; leaves opposite [Caryocar] or spiral, trifoliate, stipellate or not, leaflets ± articulated, (margins entire), stipules ± intrapetiolar [Anthodiscus] or inter-intrapetiolar; inflorescences terminal, racemose(-corymbose); pedicels articulated, bracts 0; flowers large, (6-merous), K imbricate, (small, ± connate, lobed - Anthodiscus), C protective in bud, with 3 traces, free, connate below, or forming a calyptra, deciduous; A many, connate at base and adnate to C, (in 5 bundles), filaments long, with wart-like tubercles/vesicles towards apex, inner stamens staminodial, anthers basifixed; nectary at base of G/0 [Anthodiscus], G [4-20], styles [styluli?] separate, impressed, stigmas not expanded; ovule 1/carpel, ascending, campylotropous to anatropous, epitropous, attachment broad, micropyle endostomal, outer integument 2-3 cells across, inner integument 3-4 cells across, (unitegmic, integument 4-5 cells across - Anthodiscus), weakly crassinucellate, nucellus below embryo sac very long, cells of nucellar apex radially elongated, obturator 0; fruit a drupe, (radiating fibres - Caryocar), stone separating into 1-seeded units; seeds reniform, coat undistinguished, testa aerenchymatous or not, vascularized, exotegmen?; endosperm type?, at most thin, (hypocotyl very large, oily, spirally-twisted - Anthodiscus); n = 23.

2[list]/21: Anthodiscus (15). Tropical America, esp. Amazonia (map: from Prance & Freitas da Silva 1973). [Photo - Flower] [Photo - Flower, Fruit]

• Caryocaraceae are evergreen trees to shrubs that may be recognised by their trifoliolate, stipulate and usually serrate leaves, terminal racemose inflorescences, and large flowers with very long, radiating stamens. The fruits are drupes and the seeds are reniform.

Evolution. Stem Caryocaraceae may have diverged from other Malpighiales in the Cretaceous-Albian 111-100 million years before present ([117.6-]112.3[-108.5]/[103.8-]101.7[-99.5] million years before present: Davis et al. 2005a).

Chemistry, Morphology, etc. See Hegnauer (1964, 1989, the latter also under Lecythidaceae) for chemistry. The fruits of both genera can be used as fish poisons.

Prance and Freitas da Silva (1973) described Anthodiscus as lacking stipules. See Dickison (1990c) for details of the complex floral vasculature and other floral features; in Anthodiscus each style receives a vascular bundle fromn adjacent carpels, so is presumably commissural.

Previous relationships. Both Cronquist (1981) and Takhtajan (1997) included Caryocaraceae in Theales.