EXTANT SEED PLANTS

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 rich in guaiacyl units; true roots present, apex multicellular, xylem exarch, 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 +; tracheid/tracheid pits circular, bordered; sieve tube/cell plastids with starch grains; phloem fibers +; stem cork cambium superficial, root cork cambium deep seated; nodes ?; stomata ?; leaf vascular bundles collateral; leaves megaphyllous [determinancy evolved first, then ad/abaxial symmetry], spiral, simple, axillary buds +[?], prophylls [including bracteoles] two, lateral, veins -5 mm/mm² [mean for all non-angiosperms 1.8]; 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, 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 duplication [N/O//A/C and P//BE lines], mitochondrial nad1 intron 2 and coxIIi3 intron present.

MAGNOLIOPHYTA

Plant woody, evergreen; lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, non-hydrolysable tannins, quercetin and/or kaempferol +, apigenin and/or luteolin scattered, [cyanogenesis in ANITA grade?], lignins derived from both coniferyl and sinapyl alcohols, containing syringaldehyde [in positive Maüle reaction, syringyl:guaiacyl ratio less 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; stem with 2-layered tunica-corpus construction; wood fibers and wood parenchyma +; reaction wood ?, with gelatinous fibres; starch grains simple; primary cell wall mostly with pectic polysaccharides; tracheids +; sieve tubes eunucleate, with a sieve plate and cytoplasm with P-proteins, companion cells from same mother cell that gave rise to the sieve tube; nodes unilacunar [1:?]; stomata with ends of guard cells level with pore, paracytic, outer stomatal ledges producing vestibule; leaves with petiole and lamina [the latter 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; flowers perfect, polysymmetric, parts spiral [esp. the A], free, development in general centripetal, numbers unstable; P not sharply differentiated, outer members not enclosing the rest of the bud, smaller than inner members; A many, with a single trace, introrse, filaments stout, anther ± embedded in the filament, tetrasporangiate, dithecal, 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, binucleate at dispersal, trinucleate eventually, 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, few [?1] ovules/carpel, ovules marginal, anatropous, bitegmic, [outer integument often largely subdermal in origin, inner integument dermal], micropyle endostomal, integuments 2-3 cells thick, nucellus at apex of ovule 1-3 cells thick, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte four-celled [one-modular, nucleus of egg cell sister to one of the polar nuclei], stylulus short, hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, dry [not secretory]; P deciduous in fruit; seed exotestal; pollen germinating in less than 3 hours, siphonogamy, tube elongated, growing at 80-600 µm/hour, with callose plugs and callose-based walls, penetrating between cells, penetration of ovules within ca 18 hours, distance to first ovule 1.1.-2.1 mm; tube moves between nucellar cells, double fertilisation +, endosperm diploid, cellular [first division oblique, micropylar end initially with a single large cell, chalazal end more actively dividing], copious, oily and/or proteinaceous, embryo cellular ab initio, minute; germination hypogeal, seedlings/young plants sympodial; Arabidopsis-type telomeres [(TTTAGGG)_n]; whole genome duplication, 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 PHYA + C/PHYB + E gene pairs.

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, because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied, there is considerable variation between families 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 a 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), where on the tree a thicker nucellus and a stylar epidermal layer are acquired has not yet been indicated.

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

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

ROSIDS: embryo long; genome duplication; chloroplast infA gene defunct, mitochondrial coxII.i3 intron 0.

MALVIDAE = [[GERANIALES + MYRTALES] [PICRAMNIALES [SAPINDALES [HUERTEALES [MALVALES + BRASSICALES]]]]]: ?

[GERANIALES + MYRTALES]: ellagic acid +; K persistent in fruit[!]

MYRTALES Reichenbach  Main Tree, Synapomorphies.

Flaky bark; flavonols only, myricetin, methylated ellagic acid +; cork cambium deep seated, (polyderm +); pits vestured; libriform septate fibers +; tension wood +; secondary phloem stratified in young twigs; internal phloem +; nodes 1:1; (spirally-thickened tracheoids +); cuticle waxes often 0; branching from current flush [all?]; leaves opposite, venation brochidodromous, (small stipules +), colleters +; (flowers 4-merous); hypanthium +, nectariferous, K valvate, A incurved in bud, pollen with pseudocolpi, many ovules/carpel, (transseptal bundles +), micropyle bistomal and zig-zag, style +, long, minor stylar bundles +, stigma wet; (mesotesta sclerotic), endotesta crystalliferous; endosperm at most slight. - 9 families, 380 genera, 11027 species.

• Myrtales may be recognised by their often flaky bark; opposite leaves with colleters, at most small stipules and strong intramarginal veins; flowers with petals that are clawed or at least very narrow at the base, a more or less inferior ovary, and a usually nectariferous hypanthium. The sepals are often valvate and the stamens are usually incurved in bud.

Evolution. Wikström et al. (2001) dated the origin of stem Myrtales to (103-)100(-97) million years before present, diversification beginning (82-)78(-74) million years ago. The age of crown group Myrtales was estimated as (89-)85, 78(-74) million years (two penalized likelihood dates), the stem group age being (111-)106(-101) or (86-)83(-80) million years; Bayesian relaxed clock estimates for the crown group gave dates at old as 99 million years (Wang et al. 2009), while Magallón and Castillo (2009 - topology of this part of the tree uncertain) estimated ages of ca 107.9 and 108.4 million years for relaxed and constrained penalized likelihood datings for the age of stem Myrtales alone. Fossils assignable to Myrtales are some 65 million years old (Crepet et al. 2004), Pigg et al. (1992) describing a fossil from the Paleocene that they thought was close to Myrteae-Psidium.

Myrtales contain ca 6% core eudicot diversity.

Lycaenidae caterpillars are quite commonly to be found on members of this order (esp. Lythraceae, Myrtaceae, Combretaceae - see Fielder 1991, 1995).

Chemistry, Morphology, etc. There are a number of other characters that are common in Myrtales and may be apomorphies for them. Raffinose and stachyose are common oligosaccharides in phloem exudate in Myrtaceae, Onagraceae, Lythraceae and Combretaceae, at least (Zimmermann & Ziegler 1975). Polyderm (alternating endodermal and parenchymatous layers laid down by a pericyclic meristem) is known from families like Onagraceae, Lythraceae, Myrtaceae, and probably Penaeaceae and Oliniaceae, at least (Mylius 1913), while in roots of some aquatic Lythraceae, Melastomataceae. Myrtaceae and Onagraceae (and Euphorbiaceae and Fabaceae) there is a distinctive lacunate cork produced from a pericyclic cork cambium (Little & Stockey 2006). Tracheoidal sclereids with spiral wall thickenings that are associated with the vein endings are known from Vochysiaceae, Lythraceae, Combretaceae, Melastomataceae, Alzateaceae and Penaeaceae (Sajo & Rudall 2002); their more general distribution needs to be checked. Since there is internal phloem, petiole and midrib bundles are often bicollateral. Weberling (2000) notes that "true rudimentary stipules" occur in Myrtaceae and most myrtalean families; stipules, when they occur, are indeed generally small and may be derived from colleters (see also Carr & Carr 1966). In Myrtaceae the calyx and corolla originate at about the same time, while in Lythraceae and Onagraceae the calyx is visible considerably before the corolla (Mayr 1969); it will be interesting to know the general distribution of this feature. Many Myrtales, including some Myrtaceae, have notably narrow petal bases, i.e., they are close to being clawed; the definition and distribution of clawed petals may have to be amended. Those taxa in which the stamens are straight in bud have short filaments, and the length of the style is correlated in part with the length of the hypanthial tube. Distinctive winged fruits are found in Combretaceae and rarely in Oenothera, and even more distinctive fruits that open by the placenta breaking through the ovary wall occur throughout Cuphea (Lythraceae) and in some Sonerila (Melastomataceae). The basic chromosome number for the order may be x = 12 (Graham et al. 1993).

The cork cambium is sometimes initiated in the mid-cortical position (e.g. Myrtaceae, Melastomataceae).

For further information, see Weiss (1890: cork cambium), Lourteig (1965), Venkateswarlu and Prakash Rao (1971), Beusekom-Osinga and Beusekom (1975: morphology etc. around Crypteroniaceae), Johnson and Briggs (1985: morphological phylogeny), Van Vliet and Baas (1975, 1985: vegetative anatomy), Rye (1979), Solt and Wurdack (1980: chromosome number), Tobe and Raven (1983a, 1985a, 1985b, 1987a, 1990: embryology), Dahlgren and Thorne (1985: general, and other papers in this issue of the Ann. Missouri Bot. Gard.), Boesewinkel and Venturelli (1987: ovule and seed), Weberling (1988: inflorescence morphology), Ronse Decraene & Smets (1991b: polyandry), and Almeda (1997: chromosome numbers).

Phylogeny. The position of Myrtales within the rosids was unstable in a rbcL analysis of all angiosperms (Hilu et al. 2003). However, there was some support for a position sister to all other rosids except Geraniales, Vitales and Saxifragales (Zhu et al. 2007), while Wang et al. (2009) suggested that is was sister to Geraniales, the combined group being sister to all other malvids. Phylogeny. See also the Dilleniales and the Saxifragales pages for further discussion on the relationships of Myrtales.

Relationships within the order have been extensively studied by Conti et al. (1996, 1998, 1999, 2002), Sytsma et al. (1998, esp. 2004), Clausing and Renner (2001: Melastomataceae), Schönenberger and Conti (2001, 2003: esp. Penaeaceae area, etc.) and Wilson et al. (2005: Myrtaceae s.l.), and the tree is based on these publications. The position of Combretaceae seems still to be unclear. Although anatomy (vestured pits), some morphological features (general leaf type and insertion) and molecular data strongly suggest that Vochysiaceae are to be included in Myrtales, at first sight the distinctive monosymmetric spurred flowers are quite unlike those of the other members of the order.

Includes Alzateaceae, Combretaceae, Crypteroniaceae, Lythraceae, Melastomataceae, Myrtaceae, Onagraceae, Penaeaceae, Vochysiaceae.

Synonymy: Melastomatineae J. Presl - Circaeales Lindley, Combretales Baskerville, Epilobiales Ventenat, Lythrales Caruel, Melastomatales Oliver, Memecylales de Candolle, Myrobalanales link, Oenotherales Bromhead, Onagrales Reichenbach f., Penaeales Lindley, Trapales J. Presl, Vochysiales Dumortier - Myrtanae Takhtajan - Myrtopsida Bartling, Oenotheropsida Brongniart

COMBRETACEAE R. Brown, nom. cons.   Back to Myrtales

Lianes or trees; 5-desoxyflavonoids, flavonoid sulphates +; (cork epidermal; included phloem + - Combreteae); fibers with at most minutely bordered pits; sclereids +/0; petiole bundle arcuate to annular (wing bundles +); hairs often unicellular, pointed, thick-walled, and with a basal internal compartment, (lepidote); leaves spiral or opposite, conduplicate or supervolute (revolute - Laguncularia), domatia or other glands common, stipules at most small; (plant monoecious), inflorescence racemose; flowers 4-5(-8)-merous; C often small or 0, A obdiplostemonous, (= and alternate with or opposite sepals; -15), inserted below or at the hypanthial; G [2-5(-8)], inferior, alternate with K or odd member abaxial (nectary on top), unilocular, with (1-)2-7(-20) pendulous ovules, nucellar cap +, funicles long, usu. with obturator, stigma punctate (capitate); fruit indehiscent, dry; seed large; endotesta tracheidal or sclerotic, ?not crystalliferous, fibrous exotegmen +; embryo often green, cotyledons convolute or plicate; n = (7, 11)12-13.

14[list]/500: 3 groups below. Largely tropical. [Photo - Flower, Flower, Fruit.]

1. Strephonematoideae Engler

Internal phloem 0; stomata paracytic; hairs appressed, 2-armed; leaves "alternate"; C clawed, pollen lacking pseudocolpi, only semitectate; G half inferior, 2 pendulous ovules; fruit largely superior; cotyledons large, conduplicate, hemispherical; germination hypogeal; n = ?

1/3. West Africa (map: from Jongkind 1995).

2. Combretoideae Burnett

(Petiole with glands); flowers often sessile; G inferior; fruit ± flattened and/or winged, (drupaceous); cotyledons flattened and variously folded.

13/500. Largely tropical (map: from van Steenis & van Balgooy 1966; Wickens 1976; FloraBase 2006: New World somewhat notional).

2a. Laguncularieae

Stomata cyclocytic; (lamina with glands); (C clawed); prophylls adnate to G; cotyledons spirally folded [convolute]; n = 13.

4/8. Tropical, often mangroves, esp. N. Australia.

2b. Combreteae Engler

(Mucilage ducts - Terminalia); stomata anomocytic; (C small/0), (micropyle endostomal - Guiera).

9/490. Largely tropical. Combretum (255), Terminalia (190).

• Combretaceae may not be very easy to recognise, although like other Myrtales they often have opposite leaves and the bark is often flaking. Trees quite often look rather pagoda-like, the branching following the Terminalia pattern, the branches consisting of flattened sprays of leaf rosettes. The leaves are entire and may have pellucid dots, surface glands (also on the petiole), or domatia. The indumentum is commonly adpressed and distinctive enough under the microscope; nodes are unilacunar. The flowers are often rather small and massed in spicate inflorescences, the hypanthium can be quite long, but the corolla is small or absent. The ovary is inferior, and the single-seeded fruit is often flattened and/or winged.

Evolution. The flattened and/or winged fruits are often wind- or water dispersed.

Chemistry, Morphology, etc. Keating (1985) describes the stomata as being paracytic while Dahgren and Thorne (1985) call them anomocytic; in any event, variation in stomatal morphology is extensive (Tilney 2002). Fibers are usually non-septate; those of Lythraceae are septate. For obdiplostemony, see Eckert (1966, also Tomlinson 1986). There are hairs lining the ovary loculus walls in Combretum.

Some information is taken from Graham (1964: general), Verhoeven and van der Schijff (1974: anatomy, including root cork cambium!), Jongkind (1995: Strephonema), El Ghazali et al. (1998: pollen) and Stace (2006: general).

Phylogeny. Strephonema may be sister to the rest of the family. Lumnitzera and Laguncularia, both mangrove plants, are sister taxa, but Conocarpus, also found in similar habitats, is not immediately related (Tan et al. 2002).

Synonymy: Bucidaceae Sprengel, Myrobalanaceae Martynov, Sheadendraceae G. Bertolini, Terminaliaceae Jaume Saint-Hilaire

Onagraceae + Lythraceae: tannins often not abundant, soluble oxalate accumulating; vessels in groups in the wood; fibers with at most minutely bordered pits; petiole bundle arcuate; inflorescence racemose; (flowers vertically monosymmetric), C clawed, (pollen at anthesis with starch); megasoporangiun with several megasporocytes; K persistent; fibrous exotegmen +; starch grains in nucellus; x = 8.

Chemistry, Morphology, etc. Decodon is the only typically pentamerous genus in Lythraceae (Graham 2006); see also Ludwigia (Onagraceae) - both seem to be sister to the rest of their respective families! Hence working out where floral merism changes on the tree thus becomes difficult. A number of Lythraceae have capitate stigmas, and this could be another feature uniting the two families.

ONAGRACEAE Jussieu, nom. cons.   Back to Myrtales

Often herbaceous; flavonoid sulphates +; raphides +; leaves ± flat to involute, (spiral, margins toothed, stipules 0); inflorescence raceme or spike (flowers axillary), bracteoles often 0, C often clawed, deciduous; A straight, anthers polythecate; pollen with viscin threads, starchy, (colpate), apertures protruding, ektexine paracrystalline, beaded; ovary inferior, alternating with K, stigma capitate; (placentation parietal), embryo sac 4-nucleate, monosporic [Oenothera type]; fruit a capsule opening loculicidally down the sides; exotesta often hairy or papillate, inner walls thickened and lignified (mesotestal cells thickened; endotegmic cells longitudinally elongated, "tanniniferous", inner walls thickened); endosperm nuclear, diploid.

22[list]/656 - two subfamilies below. World-wide (map: based on Raven 1963, 1967; Meusel et al. 1978, P. Hoch & W. Wagner, pers. comm.).

1. Ludwigioideae W. L. Wagner & Hoch

Flowers 4-5-merous, hypanthium 0, (A 10), pollen in tetrads (monads; large irregular clumps), nectary on G; G with central vascular bundles, style short; megasporocyte 1.

1/82: World-wide, esp. America. [Photo - Flower.]

2. Onagroideae W. L. Wagner & Hoch

Included phloem +; flowers 4-merous (2-merous - Circaea), hypanthium long, deciduous; A also (1, 2), transseptal vasular bundles +, (nucellus 10-25 cells thick), (style short; stigma 4-lobed), no minor stylar bundles (stigma divided; dry); (fruit baccate), K not persistent; n = 5+.

21/574: Epilobium (165), Oenothera (145: inc. Gaura, etc.), Fuchsia (105), Clarkia (42), Lopezia (22). World-wide, but esp. western North America. [Photo - Flower, Flower.]

• Onagraceae are herbs to shrubs that are recognisable by their usually opposite and quite often toothed leaves with small stipules and the often 4-merous flowers with an inferior ovary and a well-developed hypanthium. The calyx is usually rather thin, reflexed, and deciduous, there are up to eight stamens, and the pollen has viscin threads, so it is conspicuously clumped.

Evolution. Some caterpillars are found both on Vitaceae and Onagraceae (Forbes 1956) - and both contain raphides. Different rusts occur on Onagroideae and Jussiaeaoideae (Savile 1979b). For details of floral morphology and its relation to pollination, see Wagner et al. (2007).

Chemistry, Morphology, etc. The stipules of Ludwigia can be quite prominent. There are some very distinctive floral morphologies in Onagroideae. Thus Circaea has only two petals and two stamens, the latter being opposite the calyx. In the monosymmetric flowers of Lopezia there is only a single extrorse anther, a petaloid staminode, while the two adaxial petals may be recurved, with pseudonectaries on their claws. Gongylocarpus has sessile flowers, as is quite common in Onagraceae, but after pollination the ovary becomes completely enveloped by stem tissue. The viscin threads vary considerably in morphology, often being annular-vermiform, but also smooth or irregularly beaded (Skvarla et al. 1976). The style of Ludwigia has minor bundles, but these are absent in other members of the family.

x = 10, 11, 15 in the basal clades of Onagroideae, ?18 in Epilobeae, and 7 in Onagreae (Wagner et al. 2007). All the chromosomes in some species of Oenothera form a ring by a series of permanent translocations, the whole genome forming a single linkage units (Harte 1993 for its contributions to biology; Wagner et al. 2007). Hugo de Vries thought that the abrupt appearance of O. lamarckiana was an example of evolution, which for him was a process in which mutation = major change/speciation, but no natural selection. However, it turned out that it was a morphological variant that had occured because of the breakdown of the translocation system (cf. Linnaeus and Peloria [= Linaria, Plantaginaceae]).

For information, see Johansen (1928: hypostase presence, and correlation with the environment), Eyde (1982: floral anatomy), Tobe and Raven (1986, 1996) and Hoch et al. (1993: all variation in anther septa development, embryology), the Onagraceae website (general) and Wagner et al. (2007: superb summary).

Phylogeny. Within Ludwigia, taxa with five and those with ten stamens form separate clades (Barber et al. 2008). Knowledge of relationships along the backbone of the Onagroideae seems to be stabilising. Hauya, [Fuchsia + Circaea], Lopezia, and Gongylocarpus are successive branches (tribes) along the tree leading to [Epilobeae + Onagreae] (Levin et al. 2003, 2004), however, Ford and Gottlieb (2007) obtained a grouping [Hauya [Fuchsia + Circaea]] that was sister to other Onagroideae.

Classification. Reflecting the new, but for the most part well supported phylogeny of the family, taxon limits have had to be adjusted, so Oenothera has been expanded and Camissonia very much cut up (e.g. Levin et al. 2004); for appropriate nomenclatural changes, see Hoch and Wagner (2007). Onagraceae website contains a largely up-to-date summary of classification, etc., while Wagner et al. (2007) enumerate all supraspecific taxa.

Botanical Trivia. In 1827 Robert Brown recorded the phenomenon that is now called Brownian motion when observing the pollen grains of Clarkia pulchella.

Synonymy: Circaeaceae Ruthe, Epilobiaceae Ventenat, Fuchsiaceae Lilja, Isnardiaceae Martynov, Jussiaeaceae Martynov, Lopeziaceae Lilja, Oenotheraceae C. C. Robin

LYTHRACEAE Jaume Saint-Hilaire, nom. cons.   Back to Myrtales

Herbs to trees; quinolizidine alkaloids +; mucilage cells common; hairs uni- or bi(multi)cellular; leaves (spiral), flat to conduplicate, (margins dentate - Trapa), stipules +/0; (inflorescence determinate); flowers (3) 4 (5) 6(-16)-merous, heterostyly common; (hypanthium spurred; 0, but with K + C tube), hypanthium/K often strongly ribbed, with alternating appendages, C crumpled in bud, (0); A basically obdiplostemonous, (1 - = and opposite sepals - many, centrifugal), inserted just below C to near ovary, filaments of unequal length, (pollen pseudocolpi 0; disc at base of G); G [2-6(-many)], superior to inferior, orientation variable, (placentation parietal), (1-few ovules/carpel), archesporium multicellular, stigma capitate to punctate, also dry; fruit a capsule, dehiscence various, inc. circumscissile (indehiscent; berry), K often ± enclosing fruit; seeds flattened; testa multiplicative, many-layered (not Duabanga), exotesta various, (invaginated mucilage hairs +), endotestal cells often elongated and tracheidal/sclerotic, (endotegmen of crossing fibres); (cotyledons folded); n = (5-)8(-11, + polyploids), chromosomes 1-4 µm long.

31[list]/620: Cuphea (250), Diplusodon (75), Lagerstroemia (55 - A centrifugal), Nesaea (55 - probably to include Ammannia - then = 80), Rotala (45). Tropical, but some temperate (map: from van Balgooy 1975; Graham et al. 2005). [Photo - Flower]

• Lythraceae are herbs to trees that are recognisable by their flaky bark, opposite, entire leaves that lack gland dots, flowers with a ribbed hypanthium or K + C tube, a rather thick, valvate calyx, clawed petals that are crumpled in bud, and often 10 or more stamens of unequal lengths. The ovary is more or less superior, and the fruit is usually a capsule; the distinctive, initially inverted mucilaginous testa hairs are found in about half the genera.

Evolution. The fossil Trapago is known from deposits 65-73 million years before present, and other fossils assignable to Myrtales are perhaps slightly older (Crepet et al. 2004, for references). Sonneratia, a mangrove genus, has a long fossil record (its distinctive pollen is called Florschuetzia - Muller 1978); for the evolution of the mangrove habitat, see Rhizophoraceae. Decodon, now restricted to east North American, was widely distributed in the North Hemisphere from the Eocene onwards (Ferguson et al. 1997).

Taxa whose seeds have mucilaginous hairs are more or less myxospermous. The fruits of Cuphea open by the placenta expanding and moving laterally, breaking through both the thin ovary wall and the hypanthium; the seeds are exposed on the placenta.

Chemistry, Morphology, etc. Quite strongly monosymmetric flowers are found in some species of Cuphea, e.g. C. glutinosa. Androecial development is both centrifugal and centripetal (Weberling 1989 and references; Ronse Decraene & Smets 1991). Pollen is notably variable (Graham 2006). The stamens may be borne on one side of the flower (also in some Onagraceae) and so resulting in rather weakly monosymmetric flower - this is much more marked in Melastomataceae. Species of the large genus Cuphea consistently have eleven stamens. When G = K, the carpels may alternate with or be opposite to them, when G = 2, the carpels may be transverse or median, when G = 3, the odd carpel is adaxial (Eichler 1878; Baillon 1877; Spichiger et al. 2002). The inferior ovary of Punica granatum (pomegranate) is unique in flowering plants, appearing to have two (or three) superposed layers of carpels, the basal with axile and the others with intrusive parietal placentation; the placentation is fundamentally axile, the appearance of parietal placentation being the result of growth at the base of the ovary (Sinha & Joshi 1959 for vasculature). In the other species of the genus, P. proto-punica, there is an ordinary semi-inferior ovary. Graham and Cavalcanti (2001) suggest that x = 8 is the basic chromosome number for the family.

For general information, see Graham (2006).

Phylogeny. S. Graham et al. (2005) found some support for the topology [Decodon [[Lythrum + Peplis] remainder of the family]]; these other genera were included in two large clades, inverted mucilaginous hairs in the testa possibly being a synapomorphy. However, support along the whole back-bone was weak, and in some analyses there were two major clades in the whole family, with the three genera just mentioned forming a subclade within one of them. S. Graham et al. (2005) list characters for the major clades that they found. Sonneratiaceae - Sonneratia plus Duabanga - are not monophyletic (Shi et al. 2000; see also Huang & Shi 2002: one species per genus sampled); Sonneratia itself may be sister to Trapa. For a phylogeny of Cuphea, see Graham et al. (2006).

Classification. Some morphologically distinctive taxa until recently separated as their own families have been shown to nestle firmly within Lythraceae. These include Punicaceae, which has ellagitannins in its fruit; no xylem parenchyma; cuticle waxes as platelets; C clawed, crumpled in bud; G on two or three levels (see above), transseptal bundles +, micropyle exostomal, although bistomal according to Corner (1976]; exotestal cells columnar, fleshy, tegmen undistinguished; n = 7, 8; its alkaloids are like those of other Lythraceae). The mangrove Sonneratiaceae also is to be placed here; it, too, lacks axial xylem parenchyma; branched sclereids +; tegmen not persistent; embryo green; n = 12 . The floating aquatic Trapa, the water chestnut, (Trapaceae), is very distinctive, its flowers have four stamens, two transverse carpels, one pendulous ovule/carpel, ovule with a massive nucellar beak, and indehiscent fruit on which the calyx persists as horns; testa multiplicative; haustorial suspensor +, endosperm starchy, cotyledons very unequal; n = 20, 24.

Synonymy: Ammanniaceae Horaninow, Blattiaceae Niedenzu, Duabangaceae Takhtajan, Lagerstroemiaceae J. Agardh, Lawsoniaceae J. Agardh, Punicaceae Horaninow, nom. cons., Sonneratiaceae Engler, nom. cons., Trapaceae Dumortier

[Vochysiaceae + Myrtaceae] [Melastomataceae [Crypteroniaceae [Alzataeaceae [Rhynchocalycaceae [Penaeaceae + Oliniaceae]]]]]: ?

Chemistry, Morphology, etc. Oil glands are found in the anthers of Myrtaceae and Memecylaceae, and a number of other taxa in the Melastomataceae-Crypteroniaceae clade also have a very much expanded connective. Whether some staminal features - perhaps linked with pollination - are a higher-level apomorphy in this clade awaits further study.

Vochysiaceae + Myrtaceae: hairs simple, 1-2-celled; K and C imbricate, pollen syncolporate; style depressed in apex of gynoecium; fruit a capsule.

Evolution. Sytsma et al. (2004) discuss the age and biogeographic history of the group in some detail, noting i.a. that the present distribution of Vochysiaceae on either side of the Atlantic is likely to be the result of dispersal; they suggest that Psiloxylon may have been hopping about on islands in the Indian Ocean for almost 40 million years.

Phylogeny. Conti et al. (1996) found a well supported [Heteropyxidaceae + Psiloxylaceae] sister to [Myrtaceae + Vochysiaceae]; note, however, that the pollen grains of the first two are similar to those of Myrtaceae (Dahlgren & Thorne 1985). Monophyly of Myrtaceae s. str. (= Myrtoideae) was not strong (Conti et al. 1996, 1998). However, Wilson et al. (2005: matK only) found Myrtaceae s. str. to have 80% jacknife support, while Myrtaceae s. str. + [Heteropyxidaceae + Psiloxylaceae] (all together = Myrtaceae here) had ³95% support; a similar set of relationships occured in Sytsma et al. (2004; matK and ndhF).

VOCHYSIACEAE A. Saint-Hilaire, nom. cons.   Back to Myrtales

Trees (lianes); 5-deoxyflavonoids +; plants Al accumulators; included phloem +; leaf traces run along stem before entering petiole; pericyclic fibers at most few; sclerified bundles + (0) (secretory canals +) in pith; sclereids, mucilage cells +; cuticle waxes as ± grouped parallel platelets; stomata also paracytic; indumentum often brown, hairs T-shaped, unicellular, or stellate; leaves opposite, conduplicate, leathery, (venation eucamptodromous - Callisthene), stipules cauline, (associated large glands), sometimes colleter-like; inflorescence terminal (axillary), with lateral cincinni; flowers strongly obliquely mono- or asymmetric, hypanthium 0, K basally connate, one adaxial-lateral larger and with nectariferous spur from floral axis, (three K petaloid - Korupodendron), C 1, 5 (3), unequal; A 1, straight, more or less opposite abaxial lateral petal, (staminodes 2); G [3 (4)], odd member adaxial, many [epitropous] ovules/carpel, stigma punctate to subcapitate; fruit samaroid [by 4 or 5 accrescent K lobes] OR loculicidal capsules, seeds variously winged, testa thin, mesotesta ?not sclerotic, endotestal cells ± thickened, pectic, mesotegmic cells fibrous, thick-walled or not, or testa multiplicative, exotesta with thickened hairs, a few other layers persisting, but rest and tegmen disorganised; cotyledons folded; n = 11, 12.

7[list]/190: Vochysia (100), Qualea (60). Lowland tropical America, apart from Erismadelphus and Korupodendron from W. Africa (map: from Stafleu 1954). [Photo - Flower.]

• Vochysiaceae are readily recognisable by the combination of a rather ordinary Myrtalean vegetative body, i.e. their leaves are opposite, entire, and with lateral veins looping and joining near the lamina margin, with their rather large and distinctive monosymmetric or asymmetric flowers with a spurred calyx, sometimes spirally so, and a single stamen with a long anther and short filamen. Some taxa have large, flat, stipular glands.

Chemistry, Morphology, etc. Leaves of small saplings may have short petioles and swollen leaf bases. At least in Vochysia guatemalensis there are conspicuous, symmetrically-arranged mucilage canals in the pith. The stamen may be opposite either the abaxial-lateral C or the adjacent K; in the latter case, it is off the plane of symmetry (Kawasaki 1998; also Litt & Stevenson 2003b). The flowers are basically epigynous, the ovary being initiated in an inferior position; the superior position in the mature flower is secondary (Litt 1999; Litt & Stevenson 2003a). Baillon (18) suggested that the odd carpel is abaxial.

For anatomy, see Sajo and Rudall (2002), for floral development and morphology, see Litt and Stevenson (2003a, b), for a general account, see Kawasaki (2006).

Phylogeny. Erismieae, containing the tropical American Erisma and the West African Erismadelphus and Korupodendron, are monophyletic. They have cortical/subepidermal phellogen; G 1, ± inferior (perhaps plesiomorphic), 1-2 lateral to apical ovules/carpel; fruit samaroid, with persistent enlarged K; testa undifferentiated, with vascular bundles. Vochysieae are probably not monophyletic (Litt 1999).

Previous Relationships. Because of their monosymmetric, spurred flowers Vochysiaceae were often associated with families that are no longer thought to be at all closely related. Thus Vochysiaceae, often including Euphronia (e.g. Mabberley 1997; Takhtajan 1997: see Euphroniaceae in Malpighiales here), were placed in Celastrales by Cronquist (1981), and in Vochysiales, along with families like Malpighiaceae (in Malpighiales), Tremandraceae (= Elaeocarpaceae, in Oxalidales) and Krameriaceae (in Zygophyllales), by Takhtajan (1997).

MYRTACEAE Jussieu, nom. cons.   Back to Myrtales

Ethereal oils [usu. terpenes] +; wood fibers with distinctly bordered pits; leaves with gland dots; connective glandular [terpene-producing].

131/4620, three groups below. Worldwide, mostly tropical-warm temperate.

1. Psiloxyloideae Schmid

Plant "tanniniferous"; leaves spiral; plant dioecious; C clawed; A erect in bud, with separate traces, staminate flowers: 4 anther thecae opening separately, pistillode +; carpellate flowers: staminodia +; G [3], embryo sac bisporic, 8-nucleate; endotesta crystalliferous, cells periclinally elongated; x = 12.

Johnson and Briggs (1984) emphasized the fully superior nature of the ovary in Psiloxyloideae (= their Psiloxylaceae), with its relatively narrow base, comparing it with the more or less inferior ovary of Myrtoideae (Myrtaceae), which always had a broad base.

2/4. Southern Africa, Mascarenes.

1A. Heteropyxideae Engler & Gilg   Back to Myrtales

Trees; no axial xylem parenchyma; crystallolids as small platelets; leaves with domatia, stipules minute; (plant monoecious); staminate flowers: stamens = and opposite sepals[?] (+ 2 or 3 opposite petals); carpellate flowers: (G also [2]), ovules hemitropous, stigma capitate; seeds with 2 wings (one at micropyle), exotesta with tangentially elongated cells, walls scalariform-reticulately thickened, exotegmic cells elongated.

1/3. Central and S.E. Africa.

Synonymy: Heteropyxidaceae Engler & Gilg, nom. cons.

1B. Psiloxyleae (Croizat) A. J. Scott   Back to Myrtales

Trees; secretory canals in the young stem; vestured pits?; nodes ?; hairs 0; stipules colleter-like; (plant polygamodioecious), pedicels articulated; flowers 4-5(-6)-merous; C coriaceous, caducous, punctate, staminate flowers: A 2x C, anthers versatile; carpellate flowers: (G also [4]), ovules hemicampylotropous, style 0, stigma large, lobed; fruit baccate, punctate; exotesta cells large, exotegmen crushed.

1/1: Psiloxylum mauritianum. Mascarenes.

Synonymy: Psiloxylaceae Croizat

3. Myrtoideae Sweet   Back to Myrtales

(Ectomycorrhizal) trees; (plants Al accumulators); (hairs multicellular); sieve tubes with non-dispersive protein bodies; (stomata paracytic); leaves opposite or spiral, ptyxis variable, (2ndary veins palmate), stipules 2, or several, colleter-like, or 0; flowers (3-)4-5(-8)-merous; (K or P calyptrate, circumscissile), C (0-)4-5(-12), often deciduous; A many, conspicuous (5, = or in fascicles opposite petals (K); development centripetal; 10), pollen often syncolpate, G [2(-18], at least partly inferior, alternate or opposite petals or odd member abaxial, placentae thick, transseptal bundles +, (ovules unitegmic), (1-locular; 1-4(-10) basal ovules), minor stylar bundles 0, stigma punctate to capitate (peltate), also dry; (fruit baccate); testa multiplicative, ± sclerotic, or exotesta thickened, endotesta thickened or not (sclerotic palisade cells at the micropyle), exotegmen 0; embryo (undifferentiated - Eugenia), green or white, straight or curved, cotyledons often connate, intricately folded, etc.; n = (5-)11(12).

129[list]/5330: Eugenia (1115, to include Hexaclamys), Syzygium (1045), Eucalyptus (680 - Corymbia, if separate, 115), Eugenia (1115, to include Hexaclamys), Myrcia (400: limits unclear), Melaleuca (220), Verticordia (100), Calyptranthes (100: limits unclear), Psidium (100), Campomanesia (80), Leptospermum (80), Calytrix (75), Myrcianthes (50), Metrosideros (50: limits unclear), Darwinia (45), Xanthostemon (45), Tristania (40). Tropical, also temperate, esp in Australia (map: from Meusel et al. 1978). [Photo - Bark, Flower, Flower, Fruit.]

Synonymy: Chamelauciaceae Rudophi, Kaniaceae Nakai, Leptospermaceae F. Rudolphi, Melaleucaceae Vest, Myrrhiniaceae Arnott

• Myrtaceae are recognisable by their flaky bark, their entire, punctate leaves, and their imbricate calyx, often rather fugaceous corolla, and androecium with numerous stamens each often with an apical gland. In fact, in leaf, flower and fruit there is considerable variation. Many taxa have opposite leaves with a well-developed intramarginal vein; there is a group of genera with spiral leaves that dry a distinctive, dark, almost purplish color. Many genera have inferior ovaries and baccate fruits, while another large group of genera has ± superior ovaries and capsules.

Evolution. The floral and vegetative diversity of Myrtaceae in Australia is striking.

Tortricine moths (Epitymbiini) larvae feed on Myrtaceae leaf litter in Australia, and some other moth groups are also foliovores on this family there (Powell et al. 1999). About half the galls on Australian plants have been recorded from Myrtaceae (Mani 1964). Thus Eriococcidae (scale insects) are widely distributed on Eucalyptus and other members of the family (Gullan et al. 2005), while galls in this genus are also commonly formed in a three-way mutualistic association of a nematode Fergusobia (the actual gall-former) and the dipteran Fergusonina, which the nematode parasitises for part of its life cycle (Taylor et al. 2005; Ye et al. 2007).

In many Myrtaceae the numerous stamens with their brightly coloured filaments are the part of the flower than attracts pollinators visually, and in a number of taxa such as Callistemon, the bottle-brush, the flowers are aggregated into inflorescences all the flowers of which open simultaneously. Calothamnus has monosymmetric flowers, the upper "lip" being formed by a flattened structure, the filaments of all the stamens which are fused and form a single unit (Westerkamp & Claßen-Bockhoff 2007), while Verticordia has elaborately-fringed sepals. The anther glands produce oils, sometimes perhaps to attract pollinators, but also to help in the attachment of pollen to stylar hairs that are involved in the secondary pollen presentation that occurs in Verticordia, for example (Ladd et al. 1999).

Dry-fruited Myrtoideae are ectomycorrhizal (e.g. Smith & Read 1997).

Chemistry, Morphology, etc. For polyhydroxyalkaloid distribution (pyrrolizidine, pyrrolidine, and piperidine alkaloids), see Porter et al. (2000); they occur in Psiloxylon and some groups of Myrtoideae. 1A number of Myrtoideae produce gums, while some have high silica content in their leaves (Westbrook et al. 2009). Myrtaceae quite commonly have a more or less elaborated basal portion of the hypocotyl bearing root hairs, however, in Angophora there is a broad, disc-like structure apparently devoid of such hairs (Baranov 1957). Perianth parts of some Eucalyptus relatives are undifferentiated (Bohte & Drinnan 2005); circumscissile abscission of the hypanthium occurs in various ways. Androecial variation is extreme, even in quite closely-related taxa; even when the stamens are apparently oppositisepalous, this condition is developmentally derived from an oppositipetalous androecium (see e.g. Carrucan & Drinnan 2000; Drinnan & Carrucan 2005). There is considerable variation in ovule development (Bohte & Drinnan 2005).

For the phytochemistry of Heteropyxis, see Mohammed et al. (2009). Heteropyxideae are perhaps most similar to Myrtoideae-Leptospermeae; both wood anatomy (e.g. bordered pits) and pollen are like those of Myrtoideae (Stern & Brizicky 1958). The plant apparently lacks terpenes. The stamens have separate traces and the androecium shows no signs of being fasciated.

For ideas on the inflorescence structure of Myrtoideae, see Briggs and Johnson (1979). For general information on the family, see Schmid (1980), for general information on the very large genus Syzygium s.l., see Parnell et al. (2007), for Eucalyptus, see McKinnon et al. (2008), for fossils, see Basinger et al. (2007), for terpenes in Australian Myrtaceae, see Keszei et al. (2008), and for lamina anatomy of Brazilian Myrtoideae, see Cardoso et al. (2009).

Phylogeny. Fleshy-fruited Myrtoideae (the old Myrtoideae s. str. - see below) are largely derived and monophyletic, although the large genus Syzygium s.l. represents an independant acquisition of the fleshy fruit from that in Eugenia itself and the bulk of Myrteae (see also Johnson & Briggs 1984). For a matK phylogeny, see Wilson et al. (2005). The capsular-fruited Myrtoideae are paraphyletic (Sytsma et al. 1998; Wilson et al. 2001; Salywon et al. 2002). For phylogenetic relationships around Eucalyptus s.l., see Parra-O. et al. (2009) and references.

It is perhaps not surprising that testa anatomy correlates with fruit type: capsular fruits have exotestal seeds; baccate fruits have seeds with a generally sclerotic testa.

Classification. For a world checklist of Myrtaceae, see Govaerts et al. (2008). Myrtaceae s. str. (excluding Psiloxyloideae) were traditionally divided into Leptospermoideae - leaves spiral to opposite; fruit dry, dehiscent - and Myrtoideae - polyhydroxyalkaloids common; leaves opposite; terpenoid-containing glands in the apex of the connective, stigma dry; fruit fleshy, indehiscent. This distinction is untenable (see above). For a classification of Myrtoideae, see Wilson et al. (2005). The large genus Syzygium in the past has sometimes been synonymised under Eugenia, along with Acmena and other segregate genera, although the two are not imediately related (see Schmid 1972 for a pre-molecular resolution of the problem). Some generic limits in Myrteae are problematic (Lucas et al. 2005, 2007), while Biffin et al. (2006; see also Biffin et al. 2007) suggest that Syzygium should be delimited broadly, at least pending a better understanding of the morphological variation of this clade. Euclyptus seems to be in the process of being dismembered (Parra-O. et al. 2009 and references).

Melastomataceae [Crypteroniaceae [Alzataeaceae + Penaeaceae]]: (plants Al accumulators); (nodes swollen); branched or unbranched sclereids +/0 within same family; inflorescence cymose; connective abaxially much expanded [least in Rhynchocalycaceae], endothecium ephemeral, disc 0.

Chemistry, Morphology, etc. A number of taxa, but apparently not Melastomataceae, have more than a single branch from the leaf axil. Nodes other than simple unilacunar are quite widespread, however, a survey of nodal anatomy, particularly that of Melastomataceae, is much needed. For relationships in this area, see Conti et al. (2002).

MELASTOMATACEAE Jussieu, nom. cons.   Back to Myrtales

Included phloem +; (styloids +); 2ndary veins 2 or 4, strong, from (near) the base; C contorted, anthers with branched trace, pollen with pseudocolpi, stigma punctate; radicle bent.

18/5005. Very largely tropical, also subtropical. Two main groups below, one with...

1. Olisbeoideae Burnett

Libriform septate fibers 0; intraxylary phloem +; (nodes 1:3); sclereids, inc. terminal foliar sclereids + (0); crystal styloids + (0); petiole bundle arcuate or annular; (leaf veins lacking fibrous sheath); stomata paracytic; hairs 0 (uniseriate); stem apex frequently aborting, branching (complex) from previous flush; leaves with flat [Memecylon] or revolute [Mouriri] ptyxis, (2ndary veins pinnate), stipules + [seedlings]; pedicels articulated; flowers 4-5-merous, K imbricate or quincuncial; A 2x K (straight - Votomita), endothecium?, connective with depressed elliptic oil-producing gland (0), ovary inferior, carpels opposite petals, placentation basal, axile or parietal, 1-18(-many) apotropous ovules/carpel, stigma wet; fruit a berry; seeds large, cotyledons thick or curved, exotestal cells ± longitudinally elongated (some sclerotic hypodermal exotestal cells: Memecylon), exotegmen fibrous, massively sclerotic subhilum; embryo large (small), green, cotyledons crumpled [Memecylon]; n = 7; hypocotyl elongated or not in germination, cotyledons lobed.

6/435: Memecylon (300), Mouriri (85). Tropical (map: from Morley 1976; Schatz 2001). [Photo - Flower, Fruit.]

Synonymy: Memecylaceae Candolle, Mouririaceae Gardner

2. Melastomatoideae Seringe

182[list]/4570. Largely tropical and subtropical, esp. South America, although ca 400 spp. endemic to the Caribbean. [Photo - Flower, Fruit, Fruit.]

2A. Kibessia

Petiole bundle arcuate; stomata anomo-cyclocytic; hairs uniseriate; endothecium in inner wall of inner sporangium only, placentation parietal [ovary divided by septae]; capsule fleshy.

1/15. Southeast Asia.

Astronieae + The Rest: included phloem 0; petiole bundles variable; leaf veins lacking fibrous sheath.

2B. Astronieae Triana

Petiole bundle complex, open; stomata mostly anomocytic; hairs peltate scales; (anthers opening by slits), placentation basal to basal-axile.

4/150: Astronidium (70), Astronia (60). Indomalesia and Pacific.

2C. THE REST

Trees (lianes) herbs; petiole bundle(s) arcuate or complex; stomata variable, poly- and cyclocytic, etc.; hair types very diverse, including short-stalked glands; leaves with 2ndary veins 3 or 5 strong from (near) the base, tertiary veins at right angles to the midrib; flowers (3-)4-5(-10)-merous, (K with alternating lobes; A (= and opposite sepals, many), with pores, connective with a basal appendage or not (nectary +); G 2-15, placentation axile, (1-few ovules/carpel), (style hollow; stigma capitate); (fruit dehiscence irregular; baccate); n = (8-)9(-)12(-)17 (23, 31).

177/4305: Miconia (1000), Medinilla (400), Tibouchina (245), Sonerila (?180), Leandra (175), Clidemia (120), Gravesia (105), Microlicia (100), Tococa (50). Largely tropical and subtropical, esp. South America (map: from Quian & Ricklefs 2004; FloraBase 2007; Woodgyer 2007).

Synonymy: Blakeaceae Barnhart, Miconiaceae K. Koch, Rhexiaceae Dumortier

• Melastomataceae - Melastomatoideae are readily recognisable by their opposite, entire, exstipulate leaves with three or more strong veins ascending from at or near the base; tertiary veins are conspicuous, and run at right angles to the midrib. Hair types are notably diverse. The flowers with their contorted and often somewhat stridently pink petals and porose anthers which invert during development and have an elaborate, expanded connective, are also distinctive. In old fruits, the walls often distintegrate, leaving vertical vascular bundles behind.

• Olisbeoideae have opposite, entire leaves and swollen nodes; the venation is variable, but indumentum is absent or consists of uniseriate hairs. The blade can be minutely punctate when held up to the light, or the surface may be minutely lineate - this is because of the sclereids common in the family (the surface may also dry minutely bumpy). The rather small flowers are often blue and have inferior ovaries, but the parts are otherwise free, the calyx is valvate and there are twice as many stamens as petals; the anthers dehisce by slits and there are glands on the connectives. Most species are plants of the understorey.

Evolution. The diversity of Melastomataceae s.l. is centered in the tropical New World, Columbia alone having one third of the species and Brazil one half (Almeda et al. 2009). Morley and Dick (2003) were inclined to think that the broad outlines of diversification in the family could be linked with major tectonic (drift) events, but Renner (2004 and references) suggested that dispersal was more likely, with separate Miocene dispersal events resulting in the species found on Madagascar, for example. Bécquer-Granados et al. (2008) and Michelangeli et al. (2008b) discuss the complex biogeography of the speciose Antillean melastomes.

Epiphytes are quite common in Melastomatoideae, and some species are scramblers, whether with hook-shaped roots, or climbing with roots that attach to the support; some of the latter taxa have pseudodistichous leaves, one leaf of the pair being much reduced (Clausing & Renner 2001a). Some species of Tococa live in close association with the ant Myrmelachista which creates mono- or oligospecific "devil's gardens" by injecting formic acid into the leaves of the surrounding vegetation, which is thus suppressed (Morawetz et al. 1992; Frederickson et al. 2005). Petiolar or laminar ant domatia are quite common in Blakeeae and Miconieae; in Maieta guianensis ca 80% of the host plant's nitrogen is derived from the waste deposited by the ant Pheidole minutula that lives in the domatia (Solano & Dejean 2004).

The petals of Melastomatoideae are usually more or less widely spreading, and buzz pollination is common, flowers being visited by many species of bees in search of pollen (Renner 1989; Harter et al. 2002). Different species of bees tend to visit different species of Melastomataceae, although the bees involved are not oligolectic; thus mass-flowering Miconia cinerascens in Brazil is visited by the stingless Melipona (Harter et al. 2002) which also visits other plants. However, some taxa have nectariferous anther connectives, or nectar is produced on the corolla (Medinilla), hypanthium, or even on the stigma or on top of the ovary (some Miconia), and in these cases the contorted petals form a tube and anthers often open by longitudinal slits (although lacking an endothecium?) and pollination may be by birds (Renner 1989; Stein & Tobe 1989; Vogel 1997; Varassin et al. 2007, esp. 2008). Pollination in Olisbeoideae is similar. Genera of Apidae and Anthophoridae collect material from the oil-producing anther glands, also collecting pollen by buzz pollination. Flowers with these glands (the great majority of species has them) are blue, flowers without them are white (Buchmann & Buchmann 1981; Buchmann 1987).

Within Melastomatoideae, capsular fruits are linked with superior ovaries and fleshy fruits with inferior ovaries; fleshy fruits have arisen more than once (for the fleshy fruit of Miconia, see Cortez and Carmello-Guerreiro 2008). A few taxa with dry, dehiscent fruits have inferior ovaries, and here the fruit wall may fall away, the fruit than functioning as a capsule (Michelangeli et al. 2008a).

Chemistry, Morphology, etc. For wood anatomy, see van Vliet et al. (1981). Vessel:ray pits are simple. The roots have anthocyanins. A survey of nodal anatomy is needed; split laterals are probably quite common (see also R. A. Howard in van Vliet & Baas 1975). In Dissochaeta and Pternandra there is a prominent stipular flange below the leaves in the interpetiolar position. Ptyxis may seem to be plicate, perhaps because the secondary veins are so prominent. Monosymmetry of the flower is most evident in the androecium, and the stamens may form a serried rank on one side of the flower; I do not know the basic orientation of the flower.

For seed morphology, see Martin and Michelangeli (2009).

Within Olisbeoideae, vessel:ray pits are half bordered, and the rays are 2-5 cells wide and heterocellular, compared to 1(-4) cells wide and homocellular elsewhere in this clade. There is no anthocyanin in the root tips; cf. Melastomataceae! The leaves of Mouriri remain folded as they elongate. The floral vasculature of Mouriri is distinctive (Morley 1976). Much other information is taken from Morley (1976) and Renner (1993).

For general information, see Penneys (2004 onwards) Melastomataceae of the World. I am grateful to S. Renner for comments.

Phylogeny. Mouriri + Memecylon are sister to Pternandra, in turn sister to a Melastomataceae s. str. in ndhF trees; Morley (1953, 1976) suggested this general relationship. For the phylogeny and morphology of Melastomataceae, see Clausing and Renner (2001). Pternandra is probably sister to rest of Melastomatoideae s. str. (Clausing & Renner 2001: moderately good support in a 3-gene analysis).

A tribal classification of Melastomatoideae awaits further sampling of New World taxa in particular, and it certainly cannot be based simply on fruit types. For a phylogeny of the fleshy-fruited and speciose - but paraphyletic - Miconieae, see Michelangeli et al. (2004) and Martin et al. (2008); generic limits in Merianeae are also difficult (Schulman & Hyvönen 2003). Judd (1989) and Judd and Skean (1991) provide morphology-based phylogenetic analyses of axillary- and terminal-flowered Miconieae respecively. Sonerila may look rather distinct vegetatively, the leaf blades sometimes lacking the typical venation and having toothed margins, but it has anthers similar to those of other Melastomatoideae, although sometimes it has only three stamens, etc. Its fruits are also similar, although in some species the fruits open by the placenta breaking through the wall - cf. Cuphea (Lythraceae)! (Cellinese 1997).

Stone (2006) provided a phylogeny of Olisbeoideae; the six morphologically-based genera all have molecular support.

Classification. The inclusion of Memecylaceae in Melastomataceae was an option in A.P.G. II, and this was formalized in A.P.G. III (2009). In Miconieae members of the one genus are also considerably intermingled (Michelangeli et al. 2004; Martin et al. 2008); generic limits in Merianeae are also difficult (Schulman & Hyvönen 2003).

Crypteroniaceae [Alzateaceae + Penaeaceae]: stipules minute; stamens = and opposite petals; fruit a capsule; exotestal cells periclinally elongated, endotegmen not fibrous.

Phylogeny. Some of the relationships within this clade are only weakly supported (see Schönenberger & Conti 2003 for phylogeny and floral evolution of the whole group). Details of internal exine structure of Alzatea are similar to those of some Crypteroniaceae. Laterocytic stomata are known i.a. from Alzatea, Dactylocladus, and Rhynchocalyx (Baranova 1983). Is there a sclerotic mesotesta in all taxa? - there is in Penaeaceae.

Chemistry, Morphology, etc. For pollen of much of this group, see Muller (1975), for anatomy - very variable - see van Vliet and Baas (1975: detailed comparison within Myrtales), for gross morphology, see van Beusekom-Osinga and van Beusekom (1975), and for perianth morphology, see Schönenberger and von Balthazar (2006). Some information on Crypteronia and relatives is taken from Tobe and Raven (1983b, 1987b) and Renner (2006b: general).

Classification. Van Beusekom-Osinga and van Beusekom (1975) included Alzateaceae and Rhynchocalycaceae in their expanded Crypteroniaceae, and this may make sense - lump the lot, other things being equal? The earliest name for the combined clade would be Penaeaceae, however, great expansion was deemed too radical, but Penaeaceae has been moderately broadened to include Oliniaceae and Rhynchocalycaceae (A.P.G. III 2009).

CRYPTERONIACEAE A.-L. de Candolle, nom. cons.   Back to Myrtales

Tree; cork also subepidermal; septate fibers 0, fiber pits bordered; nodes 3:3 [by split laterals], 1:3 with girdling bundles, cortical bundles ± developed or 0; sclereids +/0; petiole bundles annular (with medullary trace) or arcuate, wing bundles +; stomata paracytic (anomocytic - Dactylandra); hairs 0 (unicellular); leaves with 2ndary veins pinnate to palmate; plant polygamodioecious, or flowers bisexual, inflorescence with long spicate or racemose branches, flowers 4-5-merous; C 0, 4-5; (A 2x K), connective thickened apically or not; (pollen bisyncolporate); G [2-6], ± inferior, placentation parietal or basal, (transseptal bundles +), 1-3 basal-many ovules/carpel, nucellar tissue disintegrates early, (endothelium + - Axinandra), style usu. slender, stigma capitate; fruit a capsule, flattened or not, K deciduous; seeds many, endotesta crystalliferous, exotesta and endotegmen tanniniferous, other layers ± persistent; n = ?

3/10. South East Asia, Malesia, Sri Lanka (map: from van Beusekom-Osinga 1977).

Evolution. Conti et al. (2002, see also Rutschmann et al. 2004 and esp. 2007) suggest that Crypteronia and relatives rafted from Gondwana (Africa) to Asia via India, with an origin any time from the Early to Late Cretaceous, a later date being favoured.

Alzateaceae + Penaeaceae: style stout.

ALZATEACEAE S. Graham   Back to Myrtales

Plants not Al accumulators, myricetin 0; septate fibers +, fiber pits barely bordered; branches tending to be several together; nodes 3:3, cortical bundles +; sclereids +; petiole bundle annular and with wing bundles; stipules 0; flowers small, 5(-6)-merous, K pointed in bud, C rudimentary even in bud, filaments short, connective wide, with backwards-directed appendage, thecae along apical margin, pollen pseudocolpi 0 [faint]; G [2], placentation intrusive parietal and with an incomplete septum, transseptal bundles +, micropyle endostomal, archesporium multicellular, embryo sac bisporic, Allium-type, stigma capitate; capsule flattened, K persistent; seeds several, winged, with hair-pin bundle, exotestal cells low, with sinuous walls, everything else collapsed; n = 14.

1/?2. Costa Rica to Peru (map: see Silverstone-Sopkin & Graham 1986). [Photo - Flowers.]

Chemistry, Morphology, etc. See Graham (1985, 2006) for general information on Alzatea.

PENAEACEAE Guillemin   Back to Myrtales

Leaves with glandular tips; x = 10.

9/29. E. and S. Africa, overwhelmingly South African, and St Helena. 3 groups below.

1. Rhynchocalyx

Myricetin 0; septate fibers +, fiber pits barely bordered; branches tending to be several together; plants Al accumulators; cork cortical; petiole bundle arcuate, sclereids + [not in stem?]; leaves with glandular tips, stipules colleter-like; flowers 6-merous, K pointed, C clawed, lobed; A with 4 loculi opening separately, epidermis only persisting; G [2 (3)], placentation parietal, transseptal bundles +, micropyle endostomal, archesporium multicellular, stigma ± punctate; capsule flattened; seeds several, winged; exotesta tanniniferous, outer wall lignified, all coat cells persist.

1/1: Rhynchocalyx lawsonioides. South Africa, coastal Natal and Transkei.

Penaea etc. + Olinia: plants not Al accumulators; non-hydrolysable tannins +; hypanthium well developed, pollen grains psilate, foot layer and tectum thick.

2. Peneaeae de Candolle

Small, evergreen, ericoid shrubs; libriform septate fibers 0; mesophyll with (spirally thickened) fibers; leaves often sessile, stipules ± colleter-like; flowers axillary, 4-merous; K petaloid, C 0, (A straight in bud; connective with branched vascular bundle), G 4, opposite petals, 2-4(-many) ascending or ascending and descending ovules/carpel, embryo sac tetrasporic, 16-celled, style also filiform, stigma capitate or lobed; fruit a capsule; seeds with funicular elaiosome; exotestal cells much developed or endotestal cells much elongated, other layer crushed, endotegmen fibrous; chalazal {"basal"] endosperm haustorium +, embryo with large hypocotyl, cotyledons tiny, suspensor 0.

7/23: Stylapterus (8). South Africa, S. and S.W. parts of the Cape. [Photo - Habit]

3. Olinieae Horaninow

Cork subepidermal; stomata variable; stipules cauline-on leaf base; flowers (4-)5-merous; ?epicalyx +, small, K ± spatulate, C concave, thick, hairy, pollen heteropolar; G [(2)4-5], inferior, opposite sepals, transseptal bundles +, 2-3 pendulous apotropous campylotropous ovules/carpel, micropyle bistomal, chalaza strongly vascularized, hypostase +, stigma ± clavate (commissural); fruit drupaceous, K not persisting; seed usually single; testa 3-4 thin-walled cells across, exotegmen fibrous; cotyledons spirally twisted or irregularly folded; n = ?15, ?20.

1/5. Africa, St. Helena. [Photo - Fruit, Flowers.]

• The stems of Penaeaceae are square, sometimes ridged, and the nodes are swollen.

Chemistry, Morphology, etc. The vegetative anatomy of Peneaeae is undistinguished, but the embryo sac of Penaea, at least, is unique. Nectar is secreted from the base of the hypanthium. Crushed or broken plant parts of Olinieae smell of almonds; they contain the cyanogenic glucoside, prunasin. The ovules have been reported as being apotropous and ascending (Baillon 1877). The interpretation of the perianth of Olinia is a matter of some dispute; here I follow the interpretation offered by Schönenberger and Conti (2003), although the exact nature of the outer whorl of very small appendages is still unclear (described as "?epicalyx" above). The haploid chromosome number of Olinia is 12, according to Takhtajan (1997), but cf. Goldblatt (1976).

See Schönenberger (2006) for general information about Rhynchocalyx; for the embryo suspensor of Penaea and relatives, see Ross and Sumner (2005), and for general information, see Schönenberger et al. (2006); and for general information about Olinia, see von Balthazar and Schönenberger (2006).

Synonymy: Henslowiaceae Lindley, Plectroniaceae Hiern, Rynchocalycaceae L. A. S. Johnson & B. G. Briggs