EXTANT SEED PLANTS

Plant woody, evergreen; nicotinic acid metabolised to trigonelline; primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins rich in guaiacyl units; true roots present, xylem exarch; shoot apical meristem complex; arbuscular mycorrhizae +; stem with ectophloic eustele, endodermis 0, xylem endarch; 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 ?; leaf vascular bundles collateral; leaves spiral, simple, axillary buds?, prophylls [including bracteoles] two, lateral; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores] +, mono[ana]sulcate, pollen exine and intine homogeneous, ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development endo/exosporic, gametes two, with cell walls; 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, 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 via tyrosine pathway, 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 sieve plate, companion cells from same mother cell that gave rise to the tube, the sieve tube with P-proteins; nodes unilacunar; stomata with ends of guard cells level with aperture, paracytic; leaves with petiole and lamina [the latter formed from the primordial leaf apex], development of venation acropetal, 2ndary veins pinnate, fine venation reticulate, vein endings free; flowers perfect, polysymmetric, parts spiral [esp. the A], free, numbers unstable, P not differentiated, outer members not enclosing the rest of the bud, A many, development centripetal, 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, pollen subspherical, binucleate at dispersal, trinucleate eventually, tectum continuous, endexine compact, lamellate only in the apertural regions, pollen tube elongated, with callose plugs, penetrating between cells, growth rate moderate, siphonogamy occuring, nectary 0, G free, several, ascidiate, with postgenital occlusion by secretion, few [?1] ovules/carpel, ovules marginal, anatropous, bitegmic, micropyle endostomal, integuments 2-3 cells thick, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte ?type, stylulus short, stigma ± decurrent, wet [secretory]; P deciduous in fruit; seed exotestal; 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; 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/PHYC gene pairs.

Possible apomorphies 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. Furthermore, details of relationships among gymnosperms will affect the level at which some of these characters are pegged.

NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]: vessels +, elements with scalariform perforation plates; pollen tectate-columellate, tectum reticulate [perforated]; nucleus of egg cell sister to one of the polar nuclei; ?genome duplication; "DEAER" motif in AP3 and PI genes lost, gaps in these genes.

PROTEALES [TROCHODENDRALES [BUXALES [GUNNERALES + CORE EUDICOTS]]]: ?

TROCHODENDRALES [BUXALES [GUNNERALES + CORE EUDICOTS]]: benzylisoquinoline alkaloids 0; euAP3 + TM6 genes [duplication of paleoAP3 gene: B class], mitochondrial rps2 gene lost.

BUXALES [GUNNERALES + CORE EUDICOTS]: ?

GUNNERALES + CORE EUDICOTS: Ellagic and gallic acids common, cyanogenesis via phenylalanine, isoleucine or valine pathways; micropyle?; PI-dB motif +, small deletion in the 18S ribosomal DNA common.

CORE EUDICOTS: Root apical meristem closed; flowers rather stereotyped: 5-merous, parts whorled, K and C distinct, K with 3 traces, A = 2x K, internal to the C whorl, (numerous, but then often fasciculate and/or centrifugal), pollen tricolporate, (nectary disc +), [G 5], [3] also common, compitum +, placentation axile, stigma not decurrent; endosperm nuclear; fruit dry, dehiscent, loculicidal [when a capsule]; euAP1 + euFUL + AGL79 genes [duplication of AP1/FUL or FUL-like gene], PLE + euAG [duplication of AG-like gene: C class], SEP1 + FBP6 genes [duplication of AGL2/3/4 gene].

SAXIFRAGALES [VITALES + ROSIDS]: Stipules +.

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.

ROSID II: Flavonols +; (cambium storied); petiole bundle(s) annular; ca 2 ovules/carpel; style +; endosperm scanty.

Huerteales [Brassicales + Malvales]:

Brassicales + Malvales: ?

MALVALES Dumortier  Main Tree, Synapomorphies.

(Cyclopropenoid fatty acids +), flavones, myricetin +; mucilage cells +; C contorted, disc 0, few ovules/carpel, style long; exotegmen much thickened and lignified, palisade. - 10 families, 338 genera, 6005 species.

• Many members of this order can be recognised by their spiral, pulvinate leaves that often have palmate venation, or at least a pair of lateral veins leaving from the very base of the blade; stellate or fasciculate hairs and their derivatives are common. The bark is often very fibrous and tough because of the stratified phloem. The calyx is sometimes valvate, the corolla often contorted, the stamens usually numerous, the capsule sometimes muricate or spiny, and the seeds or inside of the carpel walls sometimes conspicuously hairy.

Malvales contain ca 3.2% eudicot diversity (Magallón 1989). Timing the separation of clades in this group is of considerable interest given the distributions of many of the families; Ducousso et al. (2004) suggest that Dipterocarpaceae and Sarcolaenaceae had a common ancestor some 88 million years before present prior to the split of India and Madagascar, but unfortunately relationships in this area are unclear.

Taxa with ectomycorrhizal associations are common in this order, e.g. Tilioideae and ex Sterculiaceae, Dipterocarpaceae and Cistaceae (Smith and Read 1997), Sarcolaenaceae (Ducousso et al. 2004); it will be interesting to see just how widely distributed such mycorrhizae are.

Species with stratified phloem always have wedge-shaped phloem rays, Sarcolaenaceae perhaps excepted (Kubitzki & Chase 2002). The androecium is possibly basically oligomerous, and the earliest initiated or innermost members are oppositisepalous with centrifugal or lateral polyandry. Starchy endosperm may be an apomorphy for the group. For the distribution of cyclopropenoid fatty acids, which are also scattered outside Malvales, see Bayer et al. (1999). However, as Kubitzki and Chase (2002: Table 1) show, the evolution of this and other features common in the order are difficult to understand.

Elaeocarpaceae, previously usually included in or near Malvales, are placed unambiguously - if unexpectedly - in Oxalidales. Most Malvales as delimited here are included in Takhtajan's (1997) Malvanae.

Several clades within this order are quite well established, but relationships between them, as well as the position of one or two families, remain unclear. Fay et al. (1998a) and Bayer et al. (1999) discuss general relationships. These may be represented as Muntingiaceae [[[Thymelaeaceae + Sphaerosepalaceae] [Neuradaceae [Sarcolaenaceae [Dipterocarpaceae + Cistaceae]]]] [Bixaceae + Malvaceae]], but few of these relationships have much support, even after successive weighting. Dayanandan et al. (1999) and Morton et al. (1999) relationships within Dipterocarpaceae, and Alverson et al. (1998), Bayer et al. (1999) and especially Alverson et al. (1999) those within Malvaceae s.l. Neuradaceae may be sister to the rest of the order (see also Soltis et al. 2007a). Relationships between Sarcolaenaceae, Dipterocarpaceae, and Cistaceae are uncertain (Ducoussu et al. 2004). Relationships of Cytinaceae with Malvales have been suggested (Nickrent 2002), and these appeared in all analyses in a more recent study (Nickrent et al. 2004). Indeed, the strength and consistency of this association may be responsible in part for recovering a (close to) monophyletic Rafflesiales s.l., i.e. including Apodanthaceae, etc., in some analyses (see also Rafflesiaceae [Malpighiales]). However, the only taxa included in Nickrent et al. (2004) were Cistaceae and Malvaceae, and the placement of Cytinaceae remained somewhat provisional. Recently Nickrent (2007), with much better sampling, found that Cytinaceae are sister to the poorly-known Muntingiaceae with moderate (maximum likelihood) to strong (maximum parsimony) support (nuclear small-subunit [SSU] r-DNA was the nuclear gene used in the placement). Both Cytinaceae and other Malvales have exotegmic seeds, and aspects of the perianth of Cytinaceae and Malvaceae can perhaps be compared. The mitochondral genes cox1 and matR showed considerable divergence, but not the atp1 gene (Barkman et al. 2007).Apodanthaceae, here included in Cucurbitales, with which they show gynoecial similarities in particular, are somewhat similar to Malvales, both having a connate androecium and extrose anthers, inferior ovary, parietal placentation, etc. (Nickrent et al. 2004).

General information, esp. carpel orientation, is taken from from Nandi (1998b) and Kubitzki and Chase (2002); for cyclopropenoid fatty acids, see i.a. Gaydou and Ramanoelina (1983), for wood anantomy, i.a. den Outer and Vooren (1980) and den Outer and Schütz (1981).

Includes Bixaceae, Cistaceae, Cytinaceae, Dipterocarpaceae, Malvaceae, Muntingiaceae, Neuradaceae, Sarcolaenaceae, Sphaerosepalaceae, Thymelaeaceae.

Synonymy: Bixales Lindley, Cistales Reichenbach, Cytinales Dumortier, Daphnales Lindley, Neuradales Doweld, Thymelaeales Wilkomm, Tiliales Caruel - Malvidae Thorne & Reveal - Malvanae Takhtajan - Cistopsida Bartling, Daphnopsida Meisner, Malvopsida R. Brown, Thymelaeopsida Endlicher

NEURADACEAE Link, nom. cons.   Back to Malvales

Annual (perennial) herbs/subshrubs; cyclopropenoid fatty acids +, ellagic acid?, tannins?; cork?; cambium storying?; pits not bordered; sieve tube plastids with protein crystalloids and starch; nodes ?; petiole anatomy simple; cuticle waxes 0; hairs unicellular; leaves spiral, toothed to pinnatifid, 2ndary veins subpalmate, stipule 0; inflorescence modified cymose; hypanthium short, epicalyx +/0, K valvate, C also imbricate, A 10, pollen with 3 or 4 pores at each end, nectary 0, G [5-10], ± inferior, opposite C, 2-4 adaxial carpels infertile, 1-2 apical pendulous apotropous ovules/carpel, ?micropyle, styles separate, stigmas capitate; fruit dry, indehiscent, K accrescent, styles persistent, forming spines or not; exotegmic cells also tangentially elongated, crystalliferous, other tegmic cells persistent; endosperm ?development, 0, embryo bent; n = 7.

3[list]/10: Grielum (5). Africa to India, dry or desert areas. [Photo - Flower]

• Neuradaceae are rather small herbaceous or subwoody plants of warm Saharo-Indian desert areas with small, toothed, exstipulate leaves and large flowers the petals of which dry a distinctive color; there are 5-10 separate styles.

Neuradaceae have previously placed been elsewhere, as in Rosales in Cronquist (1981) and Takhtajan (1997), Hutchinson (1973) even included it in the Rosaceae, and the floral anatomy of the two is similar (Ronse Decraene & Smets 1996b). However, the corolla on drying changes color, as in some Malvaceae (Airy Shaw 1966) - see Huber (1993a). The plant probably lacks stipules, the stipule-like structures that are sometimes seen in fact being a prophyll that develops later than the foliage leaf (Bayer 2002). Goldberg (1986) notes there may be two ovules/carpel; both he and Takhtajan (1997) describe the latter as dehiscing ventrally.

For general information, see Bayer (2002); the family needs work.

Synonymy: Grielaceae Martynov

Thymelaeaceae, Sphaerosepalaceae, Bixaceae, [Cistaceae + Sarcolaenaceae + Dipterocarpaceae], Muntingiaceae, Malvaceae: pits vestured; phloem stratified, phloem rays wedge-shaped.

THYMELAEACEAE Jussieu, nom. cons.   Back to Malvales

Cyclopropenoid fatty acids +; wood often fluoresces; vascular tracheids +; secondary phloem fibers unlignified; nodes 1:1; pericyclic fibers 0 [Edgeworthia, Tepuianthus]; crystal sand +; petiole bundle arcuate; epidermal cells (massively) mucilaginous; stomata cyclocytic; hairs simple; leaves spiral, supervolute (conduplicate), stipules 0 or minute; inflorescence cymose; flowers (3-)4-5(-6)-merous, K and C imbricate, pollen trinucleate, 1 apical pendulous epitropous ovule/carpel, micropyle endostomal, antipodal cells persist, many, obturator from near base of stylar canal; (testa fleshy), exotegmen with brown contents, endotegmen with brown contents, reticulately thickened and lignified; embryo white, cotyledons large.

46-50[list]/891 - 3 groups below. World-wide, esp. trop. Africa and Australia (Map: from Domke 1934; Meusel et al. 1978). [Photo - Flower Flower, Fruit.]

1. Tepuianthus

Trees or shrubs, bark bitter; phloem rays narrow; resiniferous cells +; plant androdioecious; flowers small, K and C free, C ± clawed, 5-10 glandular scales, A 5, opposite K, 12-22, in groups opposite C?, connective produced or not, pollen colp(or)ate, G [(2)3], styles bifid [parastyles?]; seeds with an angled raphe; endosperm slight[?]; n = ?

1/7. Guayana highlands, N.E. South America.

The testa is about 6 cells thick and unlignified, then there is a layer of lignified palisade cells, the exotegmen, and immediately underneath apparently a layer of low, lignified cells, i.e., the seed coat is similar to that of other members of the family. Reports of a small embryo (Maguire & Steyermark 1981) need to be confirmed. The base of the lamina joins the petiole on the adaxial side, and so the lamina is almost peltate. Illustrations in Maguire and Steyermark (1981) suggest that there are colleters at the base of the calyx.

See Roth and Lindorf (1990) for anatomy.

Synonymy: Tepuianthaceae Maguire & Steyermark

Octolepidoideae + Thymelaeoideae: C 0, pollen oligo- to polyporate, minutely spinulose, style +, stigma ± capitate, dry; endotegmen with stripes on the inner surface.

2. Octolepidoideae Gilg

Trees, shrubs or lianes; secretory cavities + [leaves punctate]; (stomata anomocytic - Octolepis); hypanthium at most short, K (3-)5(6), valvate or imbricate, glandular scales 4-40, A 8-80, not adnate to tube, anthers usu. recurved and hippocrepiform, connective well developed, (basal layer with pendulous internal processes)G (2-)3-5(-8), (clavate or subglobose parastyles +; stigma punctate); seed arillate, with swollen funicle, or angled at the raphe; chalazal fold on ventral side only [distribution elsewhere in family?], nucellar tracheids +, (tegmen multiplicative); endosperm copious (or not?); n = ?

8/49: Gonostylus (20). Tropical Africa and Madagascar Octolepis, Malesia to Australia (Queensland), New Caledonia, Fiji.

What is the petiole anatomy of Gonystylus?

Synonymy: Gonystylaceae van Tieghem, nom. cons.

3. Thymelaeoideae Burnett

Trees, shrubs, lianes or herbs; phorbol ester diterpenes [largely orthoesters and 1-alkyldaphnane derivates], cyclopropenoid fatty acids, chelidonic acid +, myricetin, tannins 0; internal phloem +; vascular bundles bicollateral; (stomata anomocytic); leaves often opposite; inflorescence often capitate; flowers 4-5-merous, hypanthium long (0), petaloid appendages to 2 x K or 0, A 2-5, opposite (alternate with) K, or 10, pollen crotonoid, nectary disc + (long-tubular) or 0, G 2, one locule often not developed; fruit a drupe or achene; (seed with a chalazal fold, and/or caruncle +); (nucellar tracheids +; testal cells enlarged; palisade exotegmen 0; tegmen multiplicative); endosperm 0 (quite copious - e.g. Daphne, Lachnaea); n = (7-)9(10), much polyploidy.

37/690: Gnidia (140), Pimelea (110), Daphnopsis (55), Daphne (ca 100, inc. Wikstroemia, see Halda 2001), Lachnaea (40). World-wide, esp. trop. Africa and Australia.

At least some Thymelaeoideae have a lignified, torus-bearing, pit membrane (Coleman et al. 2004). Synandrodaphne lacks a floral tube. The micropyle of Gnidia is zig-zag. Eckardt (1937) discussed gynoecial variation in the group.

Synonymy: Daphnaceae Ventenat, Phaleriaceae Meisner

• Thymelaeaceae are recognisable by their very fibrous bark and entire, exstipulate often opposite leaves which frequently have rather close, parallel venation and leave prominent raised scars on the stem after they fall off; the indumentum is of unicellular hairs and is often silky-adpressed. In many taxa, the twigs are notably flexible, and plants often smell unpleasantly. The flowers are quite often in heads, and the hypanthium is often long; any corolla lobes are usually at most small. The plants are often toxic.

A number of taxa scattered through the family produce gaharu or agarwood. This is developed from the heartwood often after wounding and perhaps also infection by fungi; gaharu is much esteemed as source of incense and medecines, and some species that produce it have been decimated in the wild (Eurlings & Gravendeel 2005).

The inclusion of Tepuianthus in this clade makes eminent morphological sense (Wurdack & Horn 2001; Horn & Wurdack, ms.). It has a number of apomorphies of other Thymelaeaceae, while the features in which it differs are mostly plesiomorphies, i.e., they are similarities to other Malvales. Tepuianthus has both a well-developed corolla and scales outside the androecium, suggesting that the corolla scales of Gonostylus, and perhaps those of the rest of the family, are homologous with these glandular scales. Furthermore, although it is described as having three separate styles, the stigmas being bilobed or not, these "styles" may be similar to similar processes on top of the ovary in Gonostyloideae, which are called parastyles and associated with styles. Distinctive epidermal columns in the palisade mesophyll of the leaf of Tepuianthus are found in other Thymelaeaceae such as Solmsia, and its resin cavities may be compared with the secretory cells of Octolepidoideae. The bark of Tepuianthus is described as being bitter, while Thymelaeoideae are well known for often being rather poisonous, unfortunately, the chemistry of Octolepoideae is poorly known. Finally, the well developed parallel venation of Tepuianthus is very like that of other Thymelaeaceae, and Solmsia (New Caledonia: Octolepidoideae) is vegetatively remarkably similar to Tepuianthus down to details of the base and mucronate apex of the lamina!

The vasculature of the perianth was studied by Heinig (1951). The vasculature of the structures inside the calyx, whether paired and more or less opposite the sepals or single and in the petaline position, came from lateral branches of the sepal vasculature; equating the structures with stipules seems unlikely. Dicranolepis (Africa) has large "petals" that are variable in number but paired and opposite the petals, and they are sometimes serrate or laciniate; the anther connectives are massive.

The pollen of many Thymelaeaceae-Thymelaeoideae is similar to that of Euphorbiaceae-Crotonoideae, and the chemistry is also similar to that of Euphorbiaceae, including the presence of phorbol ester diterpenes (Seigler 1994). Microsemma (= Lethedon - Gonostyloideae) has cyclopentenoid cyanogenic glycosides; Spencer and Seigler (1985) suggested that because of this, it should be placed in Flacourtiaceae (see Achariaceae here). Thymelaeaceae were included in Myrtales by Cronquist (1981). Savolainen et al. (2000b) placed Ploiarium (ex Bonnetiaceae - Malpighiales) within Thymelaeaceae. This needs to be confirmed; morphologically and anatomically it would seem rather unlikely.

Some information is taken from Guérin (1916: ovule and seed), Domke (1934: general), Ding Hou (1960: general), Evans and Taylor (1983: phorbol esters), Wurdack and Horn (2001: Tepuianthus), van der Bank et al. (2002: phylogeny), Kubitzki (2002: Tepuianthaceae), Herber (2002a: palynology, 2002b: general), and Horn and Wurdack (ms.: general, esp. Tepuianthus). I am grateful to Z. Rogers for comments.

Sphaerosepalaceae, Bixaceae, [Cistaceae + Sarcolaenaceae + Dipterocarpaceae], Muntingiaceae, Malvaceae: hairs often stellate; stipules often well developed; A many, developing centrifugally, from 5 or 10 (15) bundles, when 5 often opposite the petals, micropyle bistomal.

SPHAEROSEPALACEAE Bullock   Back to Malvales

Deciduous trees; ellagic acid +; cambium storying ?0; pits not vestured; true tracheids +; calcium oxalate crystals +; rays uniseriate; secretory canals +; resin-filled cells outside veins; petiole bundles cylindrical (with adaxial plate; medullary bundles +); (stomata cyclocytic); hairs simple; leaves spiral or 2-ranked, conduplicate, (2ndary veins palmate; fine venation closely raised), stipule intrapetiolar, broad [± encircling stem], deciduous, petiole pulvinate; inflorescences with subumbelliform cymules; flowers usu. 4-merous, K usu. 2 + 2, caducous, outer median (persistent), inner larger, C (3-)4(-9), when 4 opposite K, clawed, aestivation various, with many short resinous lines, caducous, A with broad connective, pollen usu. ± spinose, pollen with endoapertures larger than ectoapertures, short gynophore +, nectary on top, G [2(-5)], placentation basal, 2-9 epitropous ovules/carpel, micropyle endostomal, style continuous to gynobasic, stigma punctate or obscurely lobed; fruit ± baccate, muricate to finely verrucose, ± deeply lobed, G separate, or G on one side not developed, 2-9 ovules/carpel, 1 seed/carpel; seeds with funicular aril/0, ruminate or not, testa 6-20 cells across, exotesta mucilaginous, exotegmen conspicuously incurved on either side of hypostase (not), operculum +; endosperm ?development, moderate, ruminate or not, starchy, cotyledons cordate and bilobed apically; n = ?

2[list]/18. Madagascar. [Photos - Collection]

• Sphaerosepalaceae are a small family, but with a great deal of variation. The stipules are broad, intrapetiolar, and more or less encircling the stem. The flowers are usually four merous, and the sepals are imbricate in pairs; the fruits or carpels are single seeded.

The lateral sepal bundles are commissural, as in Thymelaeaceae. There are androecial trunk bundles opposite the petals. The apparently terminal style may be modified from the gynobasic condition (Horn 2004). Secretory cavities are widespread, and the carpels produce an exudate when cut.

Takhtajan (1997) describes the stipules as being extrapetiolar and the endosperm as being copious. The rays are not storied (den Outer & Schütz 1981), and Jansen et al. (2000a) did not find vestured pits (cf. den Outer & Schütz 1981). The relationships of Sphaerosepalaceae within Malvales are unclear; in Bayer et al. (1999) they are weakly associated with Thymelaeaceae and in Alverson et al. (1998) with Bixaceae and Cochlospermaceae.

For more information, see Capuron (1962), Huard (1965), Bayer (2002) and Horn (2004).

Synonymy: Rhopalocarpaceae Takhtajan

Bixaceae + [Cistaceae + Sarcolaenaceae + Dipterocarpaceae] form a group morphologically united as follows: plant with secretory canals; K imbricate; exotegmen curved inwards in chalazal region, hypostase plug with core and annulus. Bixaceae + Cistaceae form another group: leaf teeth with a single vein proceeding to opaque deciduous apex; embryo long, cotyledons thin, curved or folded, radicle short, stout. Molecular phylogenies are largely silent about the first grouping, but suggest that the second is incorrect.

BIXACEAE Kunth, nom. cons.   Back to Malvales

Plant with secretory canals; resin-filled cells outside veins; hairs glandular, not tufted or stellate; leaf teeth with a single vein proceeding to opaque deciduous apex; inflorescence terminal, flowers large; K imbricate, anthers porose, many ovules/carpel, funicles long, micropyle zig-zag, stigma at most slightly lobed; exotegmen curved inwards in chalazal region, hypostase plug with core and annulus, outer hypostase forming the core; embryo long, cotyledons spatulate, thin, curved or folded, radicle short, stout.

4/21. Pantropical. Three groups below.

Cochlospermum et al.   Back to Malvales

Trees to ± herbs; ellagic acid +; cork ?; young stem with continuous vascular ring; sieve tube plastids with protein crystalloids and starch; petiole bundles 3, annular; glandular hairs when young; leaves spiral, palmately lobed, conduplicate, margins toothed or entire, stipules narrow; bracteoles 0; flowers ± obscurely monosymmetric, C contorted, G [3-5], opposite C or odd member adaxial, (placentation parietal); fruit a septicidal capsule, endocarp ± separating from the mesocarp; seeds hairy, tegmen with enlarged outer hypodermal cells; endosperm oily, embryo curved, ?color, cotyledons spathulate; n = 6.

2/15: Cochlospermum (12). Pantropical (Map: from Poppendieck 1980, 1981, Cochlospermum religiosum widely naturalised from Java to India). [Photo - Habit, Flower.]

• The spiral, stipulate leaves are palmately lobed. The flowers are large, more or less monosymmetric, usually yellow, and there are many stamens with porose anthers. The fruit is distinctive: it is a septicidal capsule the endocarp of which separates from the mesocarp, and the seeds are many, hairy, and curved. The plants often have a yellowish resiny exudate.

In Cochlospermum vitiifolium the median sepal is abaxial, there are no bracteoles, and the sepals are of unequal size (or three "true" sepals + two bracteoles?). There is no obvious nectary. Amoreuxia has monosymmetric flowers, the adaxial stamens being much shorter than the abaxial ones; flowers of Cochlospermum are monosymmetric in bud, and the floral vasculature is monosymmetric. The androecium has five or six bundles, and development is centrifugal. Carpel orientation needs to be checked if the flower is inverted.

The gums of Cochlospermum and those of Sterculia (Malvaceae-Sterculioideae) are similar, both containing acetylated acidic polysaccharides; Cochlospermum also has resins.

See Keating (1970, 1972) and Poppendieck (1980, 2002) for more details.

Synonymy: Cochlospermaceae Planchon, nom. cons.

Bixa + Diegodendron: glandular hairs peltate; petiole bundle cylindrical, with medullary strands; stipules ensheathing bud; G [2-4]; fruit muricate.

Bixa   Back to Malvales

Trees or shrubs; flavones, flavonols, ellagic acid, flavonoid sulphates +, proanthocyanins 0; leaves spiral, often palmate to palmately lobed, conduplicate, margins toothed to entire, 2ndary veins palmate; (flowers vertically monosymmetric); K with basal abaxial glands, C imbricate, A folded horizontally, G [2-4], opposite K, placentation parietal, inner integument 4-5 cells across; testa pulpy, endotegmen with ± thickened cells, hypodermal layer of hour-glass cells; endosperm starchy, embryo white; n = 7.

1/5. Tropical America. [Photo - Flower, Fruit, Fruits.]

• Bixa has peltate hairs, leaves with palmate venation and stipules ensheathing the bud; there is red or orange exudate. The large flowers have porose anthers folded horizontally, parietal placentation, and the seeds have a pulpy testa; the glands at the bases of the sepals are conspicuous.

The orange colouring of Bixa orellana, annatto, is used as a food colouring, e.g. for margarine.

For general information, see Poppendieck (2002).

Diegodendron Back to Malvales

Evergreen tree; cork?; nodes ?; mucilage cells?; (stomata cyclocytic); leaves 2-ranked, punctate, stipules intrapetiolar, deciduous; K unequal, C caducous, anthers with slits, disc ?inconspicuous, G [2(-4)], orientation ?, 2 basal epitropous ovules/carpel, ?micropyle, ?funicle, style gynobasic; fruit with small glands, indehiscent; seed with a glutinous outer layer, coat thin, no palisade layer, inwardly-curving exotegmen or hypostase plug, etc.; endosperm 0; n = ?

1/1: Diegodendron humbertii. Madagascar.

• Diegodendron has 2-ranked, rather short-petiolate and punctate leaves and deciduous stipules completely surrounding the stem; there are peltate glands. The flowers are quite large and are borne in a terminal panicle and the style is gynobasic. The plant is described as being aromatic.

The wood anatomy of Diegodendron is very like that of Sphaerosepalaceae (Dickison 1988), but the genus is otherwise poorly known (see also Bayer 2002).

Synonymy: Diegodendraceae Capuron

Diegodendron was included in Ochnaceae by Cronquist (1981), but excluded by Amaral (1991); Diegodendraceae were placed in Malvales by Takhtajan (1997). From molecular data (Fay et al. 1998a), Diegodendron is very similar to Bixa in particular, and the absence of any distinctive seed coat anatomy in Diegodendron is probably because the fruit is indehiscent. Diegodendron does seem morphologically rather different from the other two groups (Kubitzki & Chase 2002, Table 1), nevertheless, all three have much in common. Cochlospermaceae and Bixaceae can optionally be placed in Bixaceae s.l. (see A.P.G. II 2003), and this seems reasonable.

Cistaceae + Sarcolaenaceae + Dipterocarpaceae: ectomycorrhizae +; tracheids +; ellagic acid +; plant with secretory canals; K imbricate, two outer members often different from the rest, filaments not articulated, ovules both anatropous and straight [atropous]; exotegmen curved inwards in chalazal region, hypostase plug with core and annulus; endosperm starchy.

This grouping is strongly supported in molecular studies, albeit the sampling is poor, indeed, both Sarcolaenaceae and Cistaceae may be embedded within Dipterocarpaceae as currently circumscribed (Kubitzki & Chase 2002; Ducousso et al. 2004). Fancy the nomenclatural brouhaha that will result if this is confirmed! Nandi (1998b) noted several similarities between Cistaceae and Sarcolaenaceae (hollow style, stigma morphology, carpel number and indumentum). In both Fumana (Cistaceae) and Dipterocarpoideae the outer integument is elongated, and ectomycorrhizae are common (Appanah 1998; Ducoussu et al. 2004). Clearly, future morphological studies may well strengthen the characterisation of the whole clade, but equally clearly, clade limits within it are unclear.

CISTACEAE Jussieu, nom. cons.   Back to Malvales

Herbs to shrubs; (flavonoid sulphates +); root hairs 0; cambium storying?; phloem not stratified; nodes 1:1; mucilage cells 0?; petiole bundles arcuate; cuticle waxes 0 (platelets, annular rodlets); hairs glandular, or simple, clustered, or stellate, each cell with a basal internal compartment; leaves opposite (spiral), ± conduplicate-curved, margin toothed, 2ndary veins pinnate or palmate, stipules + or 0; K and C ± opposite, K 5, 2 outer smaller than the others (3), C (3) 5, (imbricate), crumpled in bud, A (3-)many and centrifugal, pollen often starchy, G [3(5-10)], opposite C or median member abaxial, placentation parietal (-axile), (1-)2-many straight [atropous] ovules/carpel, (anatropous, funicles short - Fumana), funicles long, style hollow, stigmas (seesile), small to capitate and/or lobed, dry, with multicellular multiseriate papillae; testa often gelatinous; embryo ± strongly curved, long, cotyledons thin, curved or folded, radicle short, stout; n = 5, 7, 9-12, etc.

8[list]/175: Helianthemum (80-110), Crocanthemum (24), Cistus (18). More or less worldwide, if scattered, often temperate or warm temperate, esp. Mediterranean region (Map: from Meusel et al. 1978). [Photos - Collection]

• Cistaceae are aromatic shrubs growing in open, sunny areas often on a sandy or chalky substrate. They often have opposite leaves with broad, even connate bases. The inner three sepals are sometimes described as being contorted, rather, the aestivation is extreme-quincuncial, the two outer sepals being much smaller than the others. The petals are free and are contorted in a direction opposite to that of the three large sepals and are crumpled when in bud; there are numerous stamens that are often sensistive to touch.

Many Cistaceae have stamens that are sensitive to touch, moving and dusting the insect with pollen.

Fumana and Lechea are successively sister to the remainder of the family; the former in particular has a number of features that are plesiomorphic in the family (Arrington 2004). Both have only three petals, the former, alone in the family, has staminodes.

For the absence of root hairs, at least in seedlings, and the fungal associations of the plant, see references in Arrington and Kubitzki (2002). Dickie et al. (2004) also mention ectomycorrhizae in Helianthemum. Wood rays are uniseriate and xylem parenchyma is almost absent (Keating 1966). Corolla initiation in Cistaceae tends to be retarded (Nandi 1998b: it is not retarded in Dipterocarpaceae, Kocyan 2005). The androecium has ten bundles, each member of the oppositisepalous whorl supplies a group of stamens while the traces of the inner whorl usually supply a single stamen only; Saunders (1936) suggested that in Cistus there are five oppositipetalous groups. At least some Cistaceae have starchy pollen grains. The embryo is green (1 record) or white (Nandi 1998a).

Takhtajan's Cistales included Cistaceae, Bixaceae and Cochlospermaceae. Corner (1976 1: 97) described Cistaceae as being "little more than variations on a single generic theme", and noted similarities between the three families mentioned.

For floral diagrams, see Eichler (1878), for general information, see Arrington and Kubitzki (2002, revised in Arrington 2004). For more information on the web, see R. Page's Cistus and Halimium website.

Synonymy: Helianthemaceae G. Meyer

Sarcolaenaceae + Dipterocarpaceae: petiole anatomy complex; stipules usu. well developed.

Perhaps sister taxa (e.g. Alverson et al. 1998), at least if Pakaraimaeoideae are excluded from Dipterocarpaceae (Kubitzki & Chase 2002).

SARCOLAENACEAE Caruel, nom. cons.   Back to Malvales

Woody, usu. evergreen; cyclopropenoid fatty acids +; cork?; wood not storied; true tracheids +; sclereids +; secretory canals?; stomata ?; hairs stellate or not; leaves 2-ranked, involute [Keller 1996], stipules caducous; inflorescence various, involucre of varying morphology subtending 1 or 2 flowers, (bract [largely two stipules] enclosing flower), K 3(-5), when 5, outer 2 smaller, C 5 (6), disc +, A (10 [Leptolaena]-)many, ± connate into 5-10 bundles or not, of 2 or 3 lengths, anther basi- or dorsifixed, pollen in tetrads, G (1) [2-4 (5)], densely hairy, placentation basically axile, (1-)2-6(-many) ovules/carpel, style hollow, stigma capitate and/or ± lobed, with multicellular papillae; fruit (indehiscent), with persistent/accrescent bracts or cupule, endocarp hairy; seed hairy or not, often ruminate; endosperm copious (0), cotyledons cordate; n = 11.

8[list]/60. Madagascar, mostly E. and C. [Photos - Collection]

• The flowers, which have a massive "involucre" and sometimes also an enclosing bract (?bracteole), and an extrastaminal disc, are distinctive. The underside of the lamina of Sarcolaena has parallel lines. The hairs are stellate.

Fossil pollen of Sarcolaenaceae is known from the Tertiary of South Africa (Coetzee & Muller 1984).

Sarcolaenaceae - "fleshy outer tunic".>/p>

For details of cyclopropenoid fatty acid distribution, see Gaydou and Ramanoelina (1983), for ectomycorrhizae, see Ducousso et al. (2004).

Synonymy: Rhodolaenaceae Bullock, Schizolaenaceae Barnhart

DIPTEROCARPACEAE Blume, nom. cons.   Back to Malvales

Trees, (ectomycorrhizal); triterpenoid dipterocarpol, sesquiterpene oleoresins +; cork also outer cortical; cambium storied; (vessel elements with scalariform plates); tyloses +; cortical bundles +; secretory cavities in pith; nodes also 5:5; petiole geniculate; stomata ?; hairs tufted, peltate, etc.; leaves spiral and 2-ranked, conduplicate(-plicate); inflorescence axillary, often branched; K (slightly connate), A initiation centrifugal, anthers ± versatile, with prolonged connective, median carpel abaxial, ovules apical, stigma slightly lobed or not; K thinnish, enlarging somewhat in fruit; seed usu. 1, testa vascularized; endosperm 0 (+), cotyledons often folded.

17[list]/680 - three groups below. Tropical, but overwhelmingly W. Malesian in species diversity (Map: from Gottwald & Parameswaran 1966; Ashton 1982).

1. Monotoideae Gilg

Rays usu. uniseriate; adaxial gland at base of lamina; androgynophore +, G [3 (4)], (1-)2 (atropous) ovules/carpel, exostome prolonged; endosperm not starchy; n = ?

3/30: Monotes (26). Africa, Madagascar, South America (Colombian Amazon: Pseudomonotes) (Map: above, area in green).

For additional information, see Catalina Londoño et al. (1995), Morton (1995).

Synonymy: Monotaceae Kostermans

2. Pakaraimoideae Maguire, Ashton & de Zeeuw

Included phloem +; rays usu. biseriate; C imbricate, shorter than K, G [5], (2-)4 ovules/carpel; n = ?

1/1: Pakaraimaea roraimae. The Guaianan Highlands, South America (Map: above, area in blue).

For additional information, see Maguire et al. (1977) and Maguire and Ashton (1980).

3. Dipterocarpoideae Burnett

Rays usu. multiseriate; resin ducts pervasive in wood; at least lateral bundles leaving central cylinder well before they enter the leaf; K imbricate [Shorea] or valvate, A (= and opposite K)-15, etc., anthers ± basifixed, pollen tricolpate, G [(2) 3] (inferior), 2(-3) ovules/carpel, micropyle endostomal; fruit usu. 1-seeded, usu. a nut, endocarp hairy, K enlarging unequally and thickish; (palisade exotegmen 0); endosperm 0 (+ - Dipterocarpus), not starchy; n = (6-)7, (10-)11(-13).

13/650: Shorea (360), Hopea (105: these two should perhaps be merged), Dipterocarpus (70), Vatica (60). Seychelles, Sri Lanka, India, South East Asia to New Guinea, but mostly W. Malesian, often dominating in mixed-species stands (Map: above, area in red). [Photo - Flower, Fruit.]

• Dipterocarpaceae are trees that may be recognised by their often 2-ranked, coriaceous leaves with strong, parallel, if not particularly close, secondary veins and scalariform tertiaries; the hairs are often fasciculate or stellate. The inflorescences are often distinctively monochasial, and the small flowers are pointed in bud and have a conspicuously contorted corolla. Distinctive fruits with strongly accrescent but often unequal sepals surrounding single-seeded nuts are common in the family, but there are other fruit types.

Dipterocarpaceae are large trees that are often dominant in the lowland forests in the area India and Sri Lanka to West Malesia, where they grow both in seasonal and everwet forests (elsewhere in the range of the family members are also often described as being abundant). Individual species tend to be mast fruiters, but in the everwet forests of S.W. Sri Lanka and West Malesia all taxa in the family tend to flower and especially fruit at the same time, apparently in response to climatic changes induced by El Niño events; this kind of behavious is very uncommon in the tropics. The ectomycorrhizal habit of the family has been implicated in this distinctive phenological behaviour, and/or predator satiation (Janzen 1974a, no mention of fungi; Ashton 1982, 2002). Dipterocarpaceae lack parasitic rust fungi (Uredinales), unlike many of the other ectomycorrhizal groups (Malloch et al. 1980); this observation should be confirmed - or not - for other members of this clade; for mycorrhizae in Pakaraimaeoideae, see Moyersoen (2006).

Bergenin, a derivative of gallic acid, is widespread. Resins are collected from a number of Dipterocarpoideae. The stipules of Stemonoporus are extremely caducous. The calyx in many Shoreeae is imbricate in fruit, while the corolla is basally connate in many Dipterocarpeae. Dipterocarpus has vascular bundles in the inner integument.

Generic limits within Dipterocarpaceae need attention (Yulita et al. 2005), Neobalanocarpus possibly even being an intergeneric hybrid (Shorea sp. X Hopea sp., see Kamiya et al. 2005).

For additional information, see Gottwald and Parameswaran (1966: wood anatomy), Ashton (1982: general, 2002: general), Kajita et al. (1998), Appanah (1998: ectomycorrhizae), Morton et al. (1999), Dayanandan et al. (1999: phylogeny), and Kocyan (2005: floral development).

Cytinaceae + Muntingiaceae: ellagitannins +; fruit a berry.

For general information about this family pair, see Nickrent (2007). Synapomorphies for the clade depend on more detailed knowledge of all aspects of the poorly-known Muntingiaceae and a comprehensive phylogeny of both families.

CYTINACEAE A. Richard   Back to Malvales

Echlorophyllous endophytic root parasites; elagitannin +; vessels 0; sieve tube plastids without starch or protein inclusions; stomata?; leaves spiral; plant monoecious or dioecious; inflorescence racemose, capitate or spicate; P 4-9, basally connate; staminate flowers: A 6-20+, extrorse, connate, monothecal, (P joined by dissepiment to both A and stylodium), nectariferous cavities between stamens, connective with terminal appendage (0), pollen 2-4-porate or 3-colpate, (in tetrads), stylodium +; carpellate flowers: staminodes?, nectary near base of style, G [8-14], inferior, placentation intrusive parietal, many uni- or bitegmic straight [atropous] tenuinucellate ovules/carpel, nucellar epidermis persists, micropyle endostomal, style +, stigma punctate-radiate, commissural; exotegmic cells thickened all around; endosperm +, embryo undifferentiated; n = ?

2/10. Mexico, Mediterranean, South Africa and Madagascar (Map: from Jalas & Suominen 1976; the Parasitic Plants Website 2004). [Photo - Collection of Cytinus, Bdallophytum - Staminate Flower, Carpellate Flower.]

• Cytinaceae are echlorophyllous parasites with racemose inflorescences, sometimes capitate, in which the individual flowers are moderately sized and easy to make out. The more or less spreading perianth is a single whorl, basaly connate, and the stamens are extrorse (staminate flowers) and the style long and expanded like a round disc at the apex (carpellate flowers).

Cytinaceae are quite often parasitic on Cistaceae (same order!). The seeds become embedded in mucilaginous material derived from the placentae and funicles (Nickrent 2007).

The outer integument, when present, is much reduced. In Cytinus Harms (1935a) reports a nectary at the base of the style and the staminal tube. The elagitannin is isoterchebin (Hegnauer in Meijer 1997).

For general information see the Parasitic Plants website (Nickrent 1998 onwards).

MUNTINGIACEAE C. Bayer, M. W. Chase & M. F. Fay   Back to Malvales

Trees; ellagic acid +; pits not vestured; tracheids +; non-dispersive protein bodies?; mucilage canals 0; petiole bundle annular, no pericyclic fibers; stomata ?; hairs stellate or tufted; leaves 2-ranked, conduplicate-subplicate [Muntingia], margins toothed, 2ndary veins pinnate to palmate, stipules 0, but prophylls basal, heteromorphic; flowers fasciculate, extra-axillary, (4-)5-merous; K valvate, basally connate, C imbricate, shortly clawed, crumpled in bud, anther wall development the basic type, pollen small, ca 10 µm, triporate, nectary on [inside of] broad disc, G [5(-7)], or inferior, opposite C, with numerous septae, placentation axile-laminar, or with bilobed axile-pendulous placentae, many ovules/carpel, archesporium multicellular, micropyle zig-zag, funicle long [Muntingia], embryo sac monosporic, tetranucleate, spore micropylar [Muntingia], style stout, stigma conical, 5-ridged, or ± capitate; K persistent or deciduous; seeds many, funicle mucilaginous, exotesta mucilaginous, endotesta crystalliferous, cells of exotegmen shortly elongated; endosperm +, diploid, starchy [details of seed taken from Muntingia alone]; n = 15.

3 [list] (Dicraspidia, Muntingia, Neotessmannia)/3. Tropical America. [Photo - Flower]

• Muntingiaceae can be recognised by their 2-ranked, toothed, leaf blades with asymmetrical bases and heteromorphic stipule-like prophylls. Their flowers are in extra-axillary fascicles, the calyx is valvate, the corolla shortly clawed and crumpled in bud, and the stamens are numerous.

Some characters of Muntingiaceae (lack of stipules; pits not vestured) might suggest that the family may be rather basal in Malvales. Characters of the young secondary tissue of Muntingia, such as widely flaring rays, stratified phloem, etc., are like those of most other Malvales. Petenaea (?Elaeocarpaceae) may also be associated with this clade (Bayer et al. 1999); the genus is described as having minute stipules (Bayer 2002).

Although Muntingiaceae appear to have stipules, this may not to be the case. Dicraspidia has strikingly asymmetric prophylls; on the adaxial side of the branch they are orbicular, foliaceous and persistent, while on the abaxial side they are linear, thin and caducous. In Muntingia only an adaxial prophyll is present, and it is narrow (Karima Gaafar, pers. comm.: the situation in Neotessmannia is unknown). Sensarma (1957) suggested that the nodes of Muntingia are trilacunar, he interpreted the prophyll as a stipule, nevertheless, nodes indeed appear to be trilacunar.

Muntingia has a superior, ovary, caducous calyx, and pendulous placentae, the two other genera have inferior ovaries, laminar placentation, and a persistent calyx (?: Neotessmannia). Muntingia has erect uniseriate hairs in addition to its tufted hairs. Stamens, etc., are borne on a massive, almost disc-like structure towards the inside of which are dense hairs; the inner side of this disc as it faces the ovary seems to be the nectarial region.

Muntingiaceae were placed in Tiliaceae - Neotessmannioideae by Takhtajan (1997).

Some information is taken from Benn and Lemke (1991) and Venkata Rao (1952); the latter suggested that there were glandular, nectar-secreting hairs in Muntingia, but the hairs seem eglandular to me. Bayer (2002) gives a general account of the family. For relationships, see Bayer et al. (1998c), for carpel orientation, see Ronse Decraene (1992), and for anatomy, see Carlquist (2005a). I am grateful to Lucia Lohmann for sending me material of Muntingia.

MALVACEAE Jussieu, nom. cons.   Back to Malvales

Shrubs to trees (herbs); cyclopropenoid fatty acids, terpenoid-based quinones +; (cork outer cortical); wood commonly fluoresces; pits not vestured; tile cells common; sieve tubes with non-dispersive protein bodies; leaves spiral or 2-ranked, usu. conduplicate(-plicate), margins entire or toothed, single vein running to the non-glandular apex, 2ndary venation palmate; inflorescence made up of modified cymose units ["bicolor units"]; (epicalyx +), K valvate, (C imbricate; 0), (androgynophore +), A (5-)many, in five groups, but fundamentally obdiplostemonous, extrorse, G [(3-)5(-many)], variable in orientation, micropyle zig-zag or endo- or exostomal, (nucellar cap +), stigma usu. dry; fruit a capsule (berry, schizocarp, etc.; muricate); endotesta crystalliferous; endosperm often starchy, embryo often green.

243[list]/4225+ - 9 groups below. Largely tropical, also temperate. [Photos - Collection]

Grewioideae + Byttnerioideae: ?

1. Grewioideae Hochreutiner

K ± free, no nectary, C adaxially with various epidermal modifications (basally with nectariferous hairs), androgynophore + (0), (nectariferous), A usu. free, first A antesepalous, additional A centrifugal, antesepalous A + (0), staminodes 0, pollen prolate, G [2-10], micropyle exo- or endostomal; n = 7-9(10).

25/770: Grewia (290), Triumfetta (150), Corchorus (40-100), Microcos (60). Pantropical (warm temperate).

Nectaries are borne on the petals in e.g. Grewia and Luehea and on the androgynophore in e.g. Triumfetta. The stamens may arise from ten, five oppositisepalous, or from ringwall primordia; the vascular supply to the stamens is variable in origin (Brunken & Bayer 2005).

For floral development, see Brunken (2003).

Synonymy: Grewiaceae Doweld & Reveal, Sparmanniaceae J. Agardh, nom. cons.

2. Byttnerioideae Burnett

Petiole bundle ± incurved-arcuate; leaves (palmate - Herrania), spiral or distichous; K usu. connate, C broad at the base [hooded; with inrolled margins], then clawed, A epipetalous, 5(-30), in antepetalous fascicles alone, antesepalous staminodes + (0), petaloid, fascicles + staminodes forming a tube, false plasmodial tapetum [contents of cells resorbed], style apically ± branched; n = (5-7) 10(-13).

26/650: Byttneria (135), Hermannia (100), Ayenia (70), Melochia (55: A 5), Theobroma (20). Pantropical, esp. South America. [Photo - Flower, Flower, Fruit.]

This subfamily often has complex "basket" flowers that are pollinated by small flies and the like. Many taxa have only five stamens, a derived condition, even although developmental work might suggest that the higher numbers are derived by doubling (Whitlock et al. 2001b).

Synonymy: Byttneriaceae R. Brown, nom. cons., Cacaoaceae T. Post & Kuntze, Hermanniaceae Durande, Lasiopetalaceae Reichenbach, Melochiaceae J. Agardh, Theobromataceae J. Agardh

Sterculioideae + Tilioideae + Dombeyoideae + Brownlowioideae + Helicteroideae + [Malvoideae + Bombacoideae]: 21 bp deletion in ndhF gene.

3. Sterculioideae Burnett

Petiole bundle annular, with medullary bundle; leaves spiral, often palmately compound [basal?]; plant monoecious, inflorescence axillary, paniculate, lacking obvious bicolor units, epicalyx 0; K petaloid, C 0, androgynophore +, (nectariferous hairs at the base), filaments connate, anthers ± sessile, wall development the basic type? [5-6 cells across], staminodia 0, G largely free, micropyle endostomal, styles +; fruit a follicle (indehiscent), (endocarp pubescent); n = (15, 16, 18) 20 (21, etc.). commonly.

12/430: Sterculia (150), Cola (125). Pantropical. [Photo - Staminate flowers, Fruit.]

Wilkie et al. (2006) suggest relationships within Sterculioideae and discuss evolution of fruit types, dispersal mechanisms, etc.; leathery follices seem to be the basal condition in the group.

Synonymy: Sterculiaceae Salisbury, nom. cons.

4. Tilioideae Arnott

Plant ectomycorrhizal; stachyose, raffinose + [phloem exudate - Tilia]; petiole bundle annular, with medullary phloem strands and inverted bundles; leaves distichous [?always]; K free, A free, staminodia and stamens antepetalous, antesepalous sector empty, G opposite K; (seeds arillate); cotyledons folded; n = 41.

3/50: Tilia (23). N. temperate, Central America (map: from Meusel et al. 1978; Hultén & Fries 1986).

Mortoniodendron is to be included in this clade (Nyffeler et al. 2005).

Synonymy: Tiliaceae Jussieu, nom. cons.

5. Dombeyoideae Beilschmied

Leaves spiral; epicalyx + (0); K connate basally to free, nectary at base, A connate (free), 10 or more, (wall development the basic type), pollen often porate, spinulose, elongated antesepalous staminodes + (0), A (5-)10-10(-30), with staminodes forming a short tube, G [(2-)5(-10)], archesporium multicellular, (nucellar cap +), outer integument 3-4 cells across, inner integument 4-5 cells across, micropyle bitegmic; endocarp often pubescent; seed with umbonate sarcotestal projections; cotyledons bifid; n = 19, 20, 30, etc.

21/381: Dombeya (225), Melhania (60). Old World tropics, St Helena, esp. Madagascar and Mascarenes.

Dombeyoideae and Tilioideae are sometimes weakly associated (Alverson et al. 1999), but the former may be sister to all other taxa in this polychotomy (Nyffeler et al. 2005).

For floral morphology and development, see Tang (1998) and Tang et al. (2006).

Synonymy: Dombeyaceae Desfontaines

6. Brownlowioideae Burret

Indumentum often lepidote; inflorescences axillary; K connate, campanulate, splitting irregularly into 2-3 lobes, A ca 30, in antepetalous bundles, anther thecae sagittate, often broadly so, staminodia antesepalous (0), petaloid, ca 2 ovules/carpel, style or styles +; K persistent; n = 10.

8/68: Pentace (25). Tropical, esp. Old World.

Synonymy: Berryaceae Doweld, Brownlowiaceae Cheek

7. Helicteroideae Meisner

(Indumentum lepidote); (secondary veins pinnate - Durioneae); K connate, petals often with lateral constrictions, androgynophore +, A usu. with short tube and/or fascicles, pollen baculate or microverrucate to suprareticulate; (seeds arillate); n = 9, 14, 20, 25, etc.

8-10/95: Helicteres (40), Durio (27). Tropical, esp. Southeast Asia and W. Malesia. [Photo - Fruit.]

Helictereae are sister to Durioneae, the latter being from Sri Lanka, Burma to West Malesia: indumentum lepidote; epicalyx initially connate; n = 14. The anthers of many Durioneae are polylocular.

Helicters isora has mi\onosymmetric flowers.

Some information is taken from Nyffeler and Baum (2000).

Synonymy: Durionaceae Cheek, Helicteraceae J. Agardh, Triplochitonaceae Schumann

Malvoideae + Bombacoideae: leaves spiral; K connate, adaxially at base with multicellular clavate nectariferous hairs, C adnate to base of A, staminal tube +, anthers bisporangiate/monothecal, (locellate [= "polysporangiate": some "basal" members]), anther thecae sessile ["basal" members], unbranched synlateral [± oppositisepalous] vascular bundle +.

Sister to the rest - or almost so - in this whole clade may be things like Fremontodendron, etc. (ex Sterculiaceae - C 0), and Quararibea, etc. (ex Bombacaceae), but with only weak support (Alverson et al. 1999; cf. Bayer et al. 1999; Baum et al. 2002). Quararibea, etc., are best placed in Malvoideae, while [Ochroma + Patinoa] and Septotheca are unplaced (Baum et al. 2004). Indeed, Baum et al. (2004) suggest that [Fremontodendron + Chiranthodendron] may be sister to the rest since they lack a 6 bp deletion in a conserved region of the matK gene found in all other members of this clade, however, there is little other evidence for this position. Taxa at these nodes would have been neotropical (Nyffeler et al. 2005).

Von Balthazar et al. (2006) suggest an interpretation of the androecium of this clade - and extend their findings to determine the basic androecial structure for Malvaceae as a whole. Each androecial unit consists of an antesepalous primordium with its own vascular supply and which remains sterile (usually). It is flanked on either side by a single primordium, each derived from a separate antepetalous primordium and that each give rise to a sessile, elongated theca. Each theca is supplied by a branch from an antepetalous vascular bundle. The androecial unit thus consists of [half anther + sterile primordium + half anther]. The androecia with numerous stalked, unithecate, staminal units so common in this clade are independently derived in Bombacoideae and Malvoideae.

8. Malvoideae Burnett

Petiole bundle annular; (epicalyx +), median K often abaxial, A from 5 antepetalous primordia, (dividing into two), centrifugal, tube often with 5 apical teeth, [staminodes in fascicle; antesepalous member], (synlateral bundle 0), tapetum plasmodial, pollen often spiny, 7+ porate, G (1[2-)3-many], styles often +, stigmas decurrent [e.g. Malva] to capitate, hairy; (fruit schizocarpic); (seeds hairy); embryo curved, cotyledons folded; n = 5-20(+).

78/1670: Hibiscus (580, inc. Pavonia, etc. - see Pfeil & Crisp 2005), Sida (200), Abutilon (100), Nototriche (100: epiphyllous inflorescences), Cristaria (75), Gossypium (40). Temperate to tropical (map: from Hultén & Fries 1986; Meusel et al. 1978). [Photo - Flower]

For groupings within Malvoideae, see La Duke and Doebley (1995: restriction site analysis) and Judd et al. (2002) and within Malveae, Tate et al. (2005: presence or absence of an epicalyx correlates very well with two major clades recognizable on analysis of ITS sequence data). For relationships within Hibisceae, see Pfeil et al. (2002) and Pfeil and Crisp (2005); generic limits around Hibiscus are especially difficult - s. str. or s. lato? Diversification and molecular evolution pick up almost together in this clade (Baum et al. 2002, 2004).

For androecial development, see Janka (2003) and von Balthazar et al. (2004).

All Malvaceae s. str. are here.

Synonymy: Chiranthodendraceae A. Gray, Hibiscaceae J. Agardh, Pentapetaceae Sprengel

9. Bombacoideae Burnett

Trunk often stout, with parenchymatous water-storage tissue, so soon becomes punky when cut, stout prickles, bark thin, often green; leaves palmate(ly lobed - e.g. Ochroma); flowers axillary, 1-2 together, (K imbricate - Ochroma), filaments usu. fasciculate, anther wall development the basic type? [5-7 cells across], pollen ± flattened, triangular, staminodes usu. 0, nucellar cap +; endocarp pubescent; embryo curved; n = 36(-46).

16/120: Pachira (24), Pseudobombax (20). Tropical, esp. America and Africa (Map: from Aubréville 1974). [Photo - Flower] [Photo - Seeds]

Ochroma may be sister to other members of this clade; its filaments are connate into a tube. However, it and Patinoa formed a clade with no obvious immediate link with Bombacoideae in some analyses (Alverson et al. 1999; see also Baum et al. 2002, 2004) and are best excluded from it.

Synonymy: Bombacaceae Kunth, nom. cons.

• Malvaceae are usually readily recognisable even when sterile by the combination of fibrous bark, alternate, stipulate leaves with toothed margins, ± palmate venation, and stellate to lepidote indumentum. Mucilage is common (not in Elaeocarpaceae!). The flowers and fruits are also distinguishable by a combination of characters. The flowers often have a valvate, connate calyx with a nectary at the base inside and a contorted corolla; the stamens are often numerous and variously connate and/or fasciculate. The inside wall of the fruit and/or the surface of the seed is often hairy.

Pollen of Bombacoideae is known from deposits 69-65 million years old (Pfeil et al. 2002 for references). Caterpillars of the nymphalid Acraea are quite commonly found on members of Malvaceae, as are members of Lycaeninae (Fielder 1995). Acanthoscelides, whose larvae eat seeds, are bruchids (Chrysomeloidea-Bruchidae/Bruchinae) that have diversified on Malvaceae s.l., esp. on Malvoideae, more than on other groups outside their primary hosts, members of Fabaceae (Kergoat et al. 2005). Seed-eating bugs of the Hemiptera-Lygaeidae-Oxycareninae are also concentrated on Malvoideae (Slater 1976). The nectary in Malvaceae is commonly found on the inside of the calyx and the corolla is fused at most basally; these two features are probably connected, because access to the nectar must be preserved. However, overall there is considerable variation in nectary - and staminodium - position and type in the family. Byttnerioideae often have complex "basket" flowers that are pollinated by small flies and the like.

For domestication of cotton (Gossypium barbadense), see Dillehay et al. (2007).

Some ex-Sterculiaceae - both the plant in general and the fruit in particular - can look like Euphorbiaceae. Leptonychia is often confused with that family; it has parietal placentation, short fibers in the exotegmen, but starchy endosperm.

Tile cells are best observed in radial section; they are of two or three main types (Manchester & Miller 1978; Carlquist 1988b; Tang et al. 2005b). Any correlation of tile cell "type" with phylogeny awaits a more completely resolved tree, thus the Durio type occurs in both Malvoideae and Byttnerioideae. Vestured pitting is reported, but probably incorrectly, from Schoutenia and Ochroma (Jansen et al. 2000a). The inflorescence in most taxa is made up of "bicolor units" - a terminal flower with three bracts, two of which may subtend cymose part inflorescences with normal bracteole number and arrangement. The epicalyx seems to be made up of these three bracts, and so a flower with an epicalyx represents a highly reduced "bicolor unit" (Bayer 1999); it has evolved several times in the family. Although the inflorescence of Sterculioideae seems to be very differently constructed from that of other Malvaceae, it, too, may be made up of much modified bicolor units (Bayer 1999). Not only are the carpels of Sterculioideae secondarily free, but in Firmiana they open early in development, exposing the developing seeds on the carpel margins; the ripe fruits with seeds attached are dispersed by wind. However, there is a compitum even in these apocarpous Sterculioideae; it develops after post-genital connation of part of the styles (Jenny 1988).

For androecial development in Malvaceae s.l. compared to that in other Malvales, see Nandi (1998b) and von Balthazar et al. (2006). The basic androecial structure in this clade may be obdiplostemonous, with stamens developing in one or both whorls; anther dehiscence is extrorse (von Balthazar et al. 2006). Although starchy pollen is common in Malvaceae in the old sense, it is not in Sterculiaceae; details of variation in the clades recognised here are unclear. The carpels are usually opposite the corolla, although not infrequently (e.g. Hibiscus, Fremontodendron, Sterculia) they are opposite the calyx; when there are three carpels, the median member may be either ad- or abaxial (reports of carpel orientation in individual taxa may conflict - e.g. Eichler 1878; Ronse Decraene 1992). The flowers of Pavonia can be monosymmetric, but I do not know the plant of symmetry.

Several taxa have palmate leaves. In Brachychiton and Adansonia there is comparable variation within a flush - the first leaf/leaves have a very short petiole and long, narrow ?phyllode, while later leaves are palmate; any intermediates have winged petioles and a few leaflets.

For a discussion of groupings in the extended family, Robert Brown's comments over 150 years ago (Brown 1814) on family limits in the Malvales (= Malvaceae here) are a good starting point. Malvaceae + Bombacaceae + Sterculiaceae + Tiliaceae make a well circumscribed group, yet the clades within it are mostly difficult to distinguish, even with flowers, so combination seems sensible (Judd & Manchester 1997; Alverson et al. 1999; Bayer et al. 1999); Cheek (2007), however, opts for wholesale dismemberment into ten families. Apart from Malvaceae, all the other families in the old Malvales are highly para- or polyphyletic. For information on relationships in the extended family, see Alverson et al. (1998, 1999) Bayer et al. (1999), and Nyffeler et al. (2005). [Grewioideae + Byttnerioideae] are probably sister to the rest of the family (see also Soltis et al. 2007a), while Sterculioideae are perhaps sister to the well supported [Malvoideae + Bombacoideae]; see the latter for relationships within it. Other relationships between the subfamilies are unclear.

For androecial morphology and development, see van Heel (1966) and von Balthazar et al. (2004), for nectary morphology, etc., see Sawidis et al. (1989 and references), for inflorescence structure, Bayer (1994, 1999), for nectaries, Vogel (2000), for gynoecial diversity in "Sterculiaceae", Jenny (1988), and for wood anatomy, Chattaway (1933b, 1937), Webber (1934), Manchester and Miller (1978), Carlquist (1988b) and Tang et al. (2005a, b). For more general information, see the Malvaceae Pages website (Hinsley 2002), Cheek (2007), and especially Bayer and Kubitzki (2002).

Synonymy: Plagianthaceae J. Agardh, Philippodendraceae Endlicher, Triplobaceae Rafinesque