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.

For discission on the relationship of Pandanales, see the Petrosaviales page.

PANDANALES Lindley   Main Tree, Synapomorphies.

Nucellar cap +; embryo minute, endosperm type? - 5 families, 36 genera, 1345 species.

Stem group Pandanales are dated to ca 124 million years before present, crown group Pandanales to ca 114 million years before present (Janssen & Bremer 2004), or the crown group may be as young as ca 50 million years before present (Bremer 2000b).

This whole grouping of families is somewhat unexpected. Stevenson et al. (2000) suggest other possible characters for the order and groups of families within it, including a 6 bp deletion in atpA and a distinctively connate androecium; tenuinucellate ovules may be another synapomorphy, and starchy endosperm is common in the order. This deletion is absent in Talbotia (Velloziaceae), whether or nor it occurs in Barbaceniopsis is unclear (cf. Davis et al. 2004). Rudall et al. (2005b) note that floral meristicity - indeed, floral construction as a whole - is rather labile in this order.

Triuridaceae are grouped with Pandanales (Chase et al. 2000a: only 18S rDNA examined) and Graham et al. (2005). However, Triuridaceae were found to be sister to Zingiberaceae in some analyses by Davis et al. (2004 - an unlikely position, if morphology means anything!), although they were more frequently within Pandanales, if varying in their relationships there. Furthermore, Nartheciaceae tended to associate with Pandanales, rather than Dioscoreales, the clade in which they are included here (q.v. for further details). Details of the phylogeny of the order are taken from Behnke et al. (2000) and especially Caddick et al. (2002a) and Davis et al. (2004, Fig. 1: in neither were Triuridaceae included). Janssen and Bremer (2003: again, no Triuridaceae) suggest a somewhat different set of relationships... Rudall and Bateman (2006), in a morphological analysis of the order, found another topology, in particular, Triuridaceae were nested within Stemonaceae, but without strong bootstrap support (<50%, hardly the robust placement claimed). There are some morphological characters supporting this position, e.g. the occurence of thick filaments, free carpels, and pollen morphology. In the past, Pandanaceae and Cyclanthaceae had often been associated with Araceae and/or Arecaceae.

Some information on pollen morphology is taken from Grayum (1992); for pollen and tapetum, etc., see Furness and Rudall (2006a).

Includes Cyclanthaceae, Pandanaceae, Stemonaceae, Triuridaceae, Velloziaceae.

Synonymy: Cyclanthales J. H. Schaffner, Stemonales Doweld, Triuridales J. D. Hooker, Velloziales Reveal - Cyclanthanae Reveal, Pandananae Reveal, Triuridanae Reveal - Triuridae Reveal - Pandanopsida Brongniart

VELLOZIACEAE Hooker, nom. cons.   Back to Pandanales

Xeromorphic; vessels also in stem and leaf; sieve tube plastids in the stem <1 µm across; stomata paracytic; P large, A bisporangiate/monothecal, pollen bi- or trinucleate, G inferior, many tenuinucellate ovules/carpel, style long; fruit capsules poricidal, loculicidal, or with intercostal apertures; endosperm with starch.

9[list]/240. South America and Africa-Madagascar to Arabia, China. [Photo - Habit, Flower.]

Acanthochlamydoideae (P. C. Kao)

Caespitose rhizomatous herb; steroidal saponins +?; vessels also in stem and leaf, elements with simple perforations; basal part of scape with a root-like vascular cylinder; raphides and tannin cells 0; midrib with back-to-back vascular bundles; leaves spiral, with basal ligule surrounding stem; inflorescence compound capitate, scapose; T basally connate, septal nectaries 0; testa cells ± elongated, tegmen tanniniferous; endosperm nuclear, embryo large; n = 19; seedling?

1/1: Acanthochlamys bracteata. S.E. Tibet and S.W. China (Map above: see Ying et al. 1993 - green). [Photo - Flower] [Photo - Fruit]

The roots are tetrach or triarch and lack pith, and so are unlike the roots of most other monocots. The remarkable anatomy of the scape has been described as "similar to that of a leaf ensheathing a rhizome" (Kao & Kubitzki 1998: 56, in fact the central part of the stem is more like a root, not a rhizome). The anthers opposite the inner tepal members are inserted higher up on the tube than the anthers opposite the outer members.

Synonymy: Acanthochlamydaceae P. C. Kao

Vellozioideae N. L. Menezes

Woody or herbaceous, adventitious roots often growing down through persistent leaf bases; biflavonoids + [Xerophyta]; (velamen +); (vessels not in stem and leaf; perforations scalariform); sieve tube plastids with angular crystals and other loosely-packed crystals; transfusion tracheids in leaf bundles, phloem in two abaxial-lateral strands; (raphides/styloids +); stomata in grooves, abaxial only, (cuticular waxes as aggregated rodlets); indumentum various; leaves (spirally)3-ranked, conduplicate-flat, midrib +, margins usu. spiny; inflorescences often single-flowered, bracteoles lateral; hypanthium +/0, T largely free (corona +, usu. adnate to [part of?] A), A in mouth of hypanthium or free (dithecal; fasciculate (A in fascicle connate); to many), anthers long, (pollen in tetrads), placentae bilobed, septal nectaries +, micropyle bistomal, endothelium and funicular obturator +, stigmas large, erect or spreading; testa ± tanniniferous, exotesta thickened or not (tegmen tanniniferous - Pleurostima); endosperm helobial, cells elongated, wall formation in small chalazal chamber precedes that in large micropylar chamber, embryo short; n = 7, 8, 17, 24 [x = 12?]; collar rhizoids +.

8/240: Vellozia (105), Barbacenia (90). South America and Africa-Madagascar (to Arabia) (Map above: see Ayensu 1973b - red).

Synonymy: Barbaceniaceae Arnott

• Velloziaceae are xeromorphic and sometimes tree-like monocots (but the "trunk" is made up largely of adventitious roots) that may be recognised by their 3-ranked leaves with persistent bases and spiny margins. The inflorescences are terminal, although often appearing axillary, and often have one flower. The flowers are rather large with petaloid tepals and a long style; there may be a corona, and the stamens can be many.

Stem group Velloziaceae are dated to ca 108 million years before present, crown group Velloziaceae to ca 14 million years before present (Janssen & Bremer 2004: note topology, Velloziaceae and Stemonaceae are sister taxa). Since Acanthochlamys was not included, the crown group age refers only to Vellozioideae. Velloziaceae include many dessication-tolerant and arborescent taxa. The true stem is small, and soon rots away, the trunk being made up both of adventitious roots, each initially with a velamen, and of persistent leaf bases (Porembski 2006).

The leaves of Acanthochlamys have a rather large basal adaxial ligule ensheathing the stem; the other genera have sheathing bases. Phloem in the "midrib" bundles of the leaves is sometimes arcuate, but in smaller bundles in particular it is broken up into two abaxial-lateral strands (Smith & Ayensu 1976). Amaral and Mello-Silva (2005) suggest that the tetracytic stomata described from the Vellozioideae are more correctly to be thought of as paracytic. What is described here as the hypanthium in Velloziaceae may bear the same indumentum as occurs on the petiole; assuming the traditional interpretation of hypanthium, the perianth members must be considered to be usually more or less free. Even so, the stamens may be adnate to the tepals for most of their length, as in Barbaceniopsis.

Talbotia (African) is mesophytic and its filaments are not adnate to the perianth. It is perhaps sister to the other Vellozioideae (but cf. Behnke et al. 2000), however, basal relationships are unresolved. Barbacenia is paraphyletic, but Barbacenioideae are monophyletic (corona +; n = 7). Vellozioideae sensu Menezes are paraphyletic (Salatino et al. 2001), however, there is in general considerable disagreement between the topologies implicit in different morphology-based classifications of the family (Mello-Silva 2005), and that in Mello-Silva is only partly congruent with that of the molecular tree of Behnke et al. (2000). Nevertheless, Acanthochalmys is clearly sister to and morphologically and anatomically rather different from the rest of family (Behnke et al. 2000; Mello-Silva 2005).

Information is taken from Ayensu (1973a: general), Smith and Ayensu (1976: monograph - with anatomy - of New World taxa), de Menezes (1980: androecial evolution), Williams et al. (1991: chemistry), Kubitzki (1998b: general), Kao and Kubitzki (1998: Acanthochlamydaceae, much detail), Behnke et al. (2000: phylogeny) and Strassburg and de Menezes (2001: development).

Triuridaceae + Stemonaceae + [Pandanaceae + Cyclanthaceae]: septal nectaries 0.

TRIURIDACEAE Gardner, nom. cons.   Back to Pandanales

Echlorophyllous mycoheterotrophic herbs; chemistry?; hairs 0; vessels 0; stem with a ring of bundles (endodermis +); crystals 0; cuticular waxes as parallel platelets; stomata 0; leaves spiral, (base sheathing; closed); plant usu. mono- or dioecious, inflorescence a raceme, bracteole 0; T with median member of outer whorl adaxial [?always], 3, 6 (4-10), valvate, ± connate, A 3, 6 (2-8), extrorse to introrse, connate or not, (monothecal; dehiscing by apical slits), tapetum cells uninuclear, (plasmodial - Sciaphilieae), pollen trinucleate, inaperturate, (monosulcate - Sciaphila), surface gemmate, gemmae with protruberances or spines, filaments thick, G 10-many, centrifugal, plicate, 1 (2 - Kupea) basal tenuinucellate ovule/carpel, nucellar cap 0, endothelium +, styles (basal), solid, stigma penicillate to smooth, ?dry; fruit an achene, or dehiscing abaxially; seed (exo- and) endotestal; endosperm ?development, hemicellulosic (starch in young Triurideae), copious; n = 9, 11, 12(-16); seedling?

8[list]/48. Pantropical, but few in Africa (Map: from van de Meerendonk 1984; Maas & Rübsamen 1986). [Photo - Sciaphila, Triuris.]

• Triuridaceae are mostly rather small echlorophyllous mycoheterotrophic saprophytes with small flowers that have pointed tepals and many separate carpels; the latter often have a decidedly irregular surface in fruit.

Fossil flowers of Triuridaceae (two genera) are known from ca 90 million years before present in New Jersey (Gandolfo et al. 1998, 2002) and until recently were the earliest monocot fossils known (that honour has now been taken by Araceae - see Friis et al. 2004). Lacandonia selfs by pollen grains germinating in the anther and growing through tissue of the flower to the ovule (Márquez-Guzmán et al. 1989).

The roots lack pith (von Guttenberg 1968) and the root stele is monarch or diarch. Staminate and carpellate flowers usually lack rudiments of pistils and stamens respectively. The clearly separate and numerous carpels represent a reversion; in the past, Triuridaceae have been associated with Alismataceae and relatives (also polycarpic - see Alismatales). Lacandonia schismatica has stamens borne inside the carpels, unique in angiosperms, but the origin of this odd morphology is unclear. Although it has been suggested that these "flowers" may be pseudanthia (Rudall 2003), very recent work by Ambrose et al. (2006) suggests that heterotopy is a more likely explanation. In the perfect flowers of Lacandonia and carpellate flowers of Triuris individual primordia develop from compound primordia, and in the former stamen and carpel primordia develop from a common precursor. In any event, recognition of Lacandonia as a genus may make Triuris paraphyletic (Vergara-Silva et al. 2003); if this relationship is confirmed, the phylogenetic context for any evolutionary explanation of the distinctive floral construction becomes very specific indeed. Although the flowers of Triuridaceae are tiny, those of Kupea and Kihansia are quite strongly monosymmetric (Rudall et al. 2007b).

For floral development, see Rübsamen-Weustenfeld (1991) and Rudall (2003b), for carpels, etc., Igersheim et al. (2001), for pollen, etc., Furness et al. (2002a), and for general information, Maas-van der Kamer and Weustenfeld (1998) and Cheek et al. (2003).

Synonymy: Lacandoniaceae E. Martínes & Ramos

Stemonaceae + Pandanaceae + Cyclanthaceae: (styloids +); flowers other than 3-merous; placentation parietal, style 0.

STEMONACEAE Caruel, nom. cons.   Back to Pandanales

Tuberous or rhizomatous, with scale leaves and erect (twining) stem; (unspecified saponins - Stemona), alkaloids +; stem vascular bundles in 1 or 2 rings, those of inner or only ring amphivasal; vessels with scalariform perforations also in stem; petiole bundles in arc; (styloids +); hairs 0; leaves 2-ranked or opposite, petiolate, midrib simple (not distinct), cross veins fine, well developed, scale leaves sheathing; inflorescences axillary, cymose or flowers single; pedicel articulated; flowers 2-merous, T 4, perianth tube short, A adnate to base of T, 4, connective expanded, G 1 to [3], inferior, placentae apical or basal, 2 to many ovules/carpel, style branches ± separate; fruit a capsule [?type]; seed with elaiosome of uniseriate or vesicular hairs from hilum raphe or micropyle; testa several-layered, ridged, ridges many cells high, tanniniferous, (tegmen persists); endosperm copious, ?starch, walls not pitted; n = 7, 9, 12; cotyledon not photosynthetic, primary root well developed.

4[list]/27. China and Japan to Australia, S.E. U. S. A. (Croomia ) (Map: from Duyfjes 1993; Fl. N. Am. 26: 2002). [Croomia - Habit].

• Stemonaceae can be recognised by their elegant leaves with a petiole, sometimes a distinct midrib, and very close to distant longitudinal veins; there are conspicuous cross veins. When dry, the leaves are often very thin. The inflorescences are axillary and the flowers are 4- or 5-merous.

Stem group Stemonaceae are dated to ca 108 million years before present, crown group Stemonaceae to ca 84 million years before present (Janssen & Bremer 2004).

Duyfjes (1992) inadvertently suggested that Stemonaceae s. str. lack scale leaves. These are well documented on the underground parts (e.g. Tomlinson & Ayensu 1968), while van Steenis (1982) noted that they were sheathing and compared this feature to the sheathing photosynthetic leaves of Pentastemona, suggesting an equivalence. The morphology of the inflorescence and the nature of the breeding system of Pentastemona need more study - also its anatomy, chemistry, etc. At least some Stemonaceae are pollen flowers (Vogel 1981).

Pentastemona appears to be well embedded within the family (e.g. Jiang et al. 2006, but cf. Rudall & Bateman 2006). It can be briefly characterised as follows: Succulent monopodial herbs, scale leaves 0; hairs uniseriate; stem and petiole vascular bundles?; stomata para- or tetracytic; leaves spiral, with compound midrib, sheath ?closed; inflorescences (branched) racemose; flowers 5-merous, perianth tube long to short, A 5, connate into a fleshy ring and basally adnate to T and connectives apically adnate to stigmas, pollen inaperturate [functionally monoaperturate], atectate, G inferior, placentation parietal, many ovules/carpel, stigmatic lobes well developed; fruit a berry; seed arillate; sarcoexotesta +, endotesta with massive U-shaped thickenings; seedling? The distinctive alkaloids found in Stemonaceae with their pyrrolo- or pyrido(1,2,-alpha) azepine nucleus (see also Pilli & Ferreira de Oliveira 2000) are probably an apomorphy of the family.

Information is taken from Tomlinson and Ayensu (1968: Croomia), van Steenis (1982: Pentastemona), Duyfjes (1991: general), Bouman and Devente (1992: ovules and seeds), Kubitzki (1998b: general), Furness and Rudall (2000b: pollen aperture number) and Rudall et al. (2005b: floral morphology).

Synonymy: Croomiaceae Nakai, Pentastemonaceae Duyfjes, Roxburghiaceae Wallich

Pandanaceae + Cyclanthaceae: stem vascular bundles compound; styloids +; stomata tetracytic; inflorescence bracts conspicuous, inflorescence a spadix [flowers congested, sessile], imperfect; staminate flowers: stamens usu. several-many, pollen porate, pistillode +; carpellate flowers: staminodes +, subepidermal nucellar/chalazal cells radiating; fruit an indehiscent syncarp [baccate or drupaceous]; endotesta well developed, internally with two persistent cuticular layers; cotyledon not photosynthetic, seedling with all internodes ± elongated.

The divergence between the two families can be dated to ca. 98 million years before present (Janssen & Bremer 2004).

A close relationship between this pair of families in consistently obtained in molecular studies and also has strong morphological support.

Furness and Rudall (2006) suggest that pollen of Cyclanthaceae, alone in the order, lack endexine lamellae.

PANDANACEAE R. Brown, nom. cons.   Back to Pandanales

Woody trees, shrubs, or climbers, with roots from leaf axils, not rhizomatous; vessels elements also in stem and leaf, perforation plates scalariform; sieve tube plastids also with peripheral fibers; (leaf wax platelets aggregated); leaves spirally three- or four-ranked, conduplicate-flat, M-shaped when mature, spiny, (sheaths closed; base auriculate - Freycinetia); plant di-(mon)oecious; (inflorescence paniculate - Sararanga), inflorescence bracts usually colored; P connate as cupule [Sararanga] or vestigial; staminate flowers: A 2-many, variously aggregated [on underside of peltate structure], pollen exine three-layered [level?], (pistillode 0); carpellate flowers: (staminodes 0), G 1-several, free to connate, intra-ovarian trichomes +, (1 ovule/carpel - Freycinetia), (bisporic - Pandanus), obturator and hypostase +; fruit baccate or drupaceous; coat thin (testa ca 5 layers thick, exotesta developed - Sararanga, endotesta developed - some Freycinetia); endosperm nuclear (starchy); n = 25, 28, 30; hypocotyl long [Freycinetia], primary root branched [Pandanus].

4[list]/885: Pandanus (700), Freycinetia (180). W. Africa to the Pacific (Map: see Heywood (1978: Africa); Callmander et al. 2003). [Photo - Staminate Flower] [Photo - Carpellate Flower]

• Pandanaceae are woody plants with long, spiny-toothed leaves that are curved-flat in bud; the inflorescence is terminal and usually (elongated-)capitate and the perianth is at most vestigial.

Crown group Pandanaceae diverge ca 51 million years before present (Janssen & Bremer 2004). The pollen genus Pandaniidites is known from North America where it spans the Cretaceous-Tertiary boundary; it has been found in rocks up to 70 million years old (Hotton et al. 1994). This perhaps suggests that Pandaniidites grew in a tropical climate, however, it has since been shown that Pandaniidites pollen is associated with flowers of Limnobiophyllum, to be assigned to Araceae-Lemnoideae (Stockey et al. 1997; Stockey 2006)!

There are vessels in the leaves (but not in Cyclanthaceae). Since there is no perianth, the position of the ovary is often difficult to ascertain, but it is clearly superior in some Freycinetia (e.g. Huynh 1991). The embryo sac of Pandanus appears to have extra antipodal cells, however, these come from the nucellus.

Information, including testa anatomy, is taken from Fagerlind (1940: Pandanus seems not always to have a bisporic embryo sac), Zimmermann et al. (1974: vascular organization in the stem), Dahlgren et al. (1985: general), Hotton et al. (1994: pollen), Stevenson and Loconte (1995: phylogeny), Cox et al. (1995: phylogeny), Stone et al. (1998; general), Huynh (2001: Sararanga) and Callmander et al. (2003: phylogeny and morphology).

Synonymy: Freycinetiaceae Le Maout & Decaisne

CYCLANTHACEAE A. Richard, nom. cons.   Back to Pandanales

Herbs; vascular tracheids or vessels in root and leaf; petiole bundles scattered; (mucilage cells +); leaves spirally two-ranked, petiolate, basically simple, plicate or variants, often divided deeply, sheath?; plant monoecious, inflorescence a spadix, inflorescence bracts [spathe] colored or not; ovules tenuinucellate, micropyle bistomal; endosperm helobial, embryo short; seeds with palisade endotesta; collar rhizoids +.

12/225: Central and tropical South America (Map: from Harling 1958).[List]

Cyclanthoideae

Subepidermal sclereids +; non-articulated laticifers +; lysigenous air spaces with transverse septae +; leaves modified plicate, 2-costate; inflorescence with whorls of staminate and carpellate "flowers", P 0; staminate flowers: A in 4 rows per whorl, connate basally; carpellate flowers: ovary cavity with closely-set placentae, nucellar cap 0, funicles long; fruit dry, syncarpous, splitting down the middle of the carpellary annulus; seeds embedded in mucilage; n = 9.

1/1: Cyclanthus bipartitus. Central and N. South America, the Lesser Antilles. [Photo - Flower]

Carludovicioideae

(Climbers); cork subepidermal or outer cortical; (styloids +); leaves (2-ranked), 1- or 3-costate; P 10-30, with abaxial gland; inflorescences (axillary), flowers in spirals; staminate flowers: P in one or two whorls, 6+, A ca 10-many, filaments swollen basally; carpellate flowers: 4(-8)-merous, staminodes opposite P, long-filiform, G 4, ± inferior, alt. with P (placentae apical), many ovules/carpel; fruit baccate, syncarpous or not, apically circumscissile or with other unusual methods of opening; (seeds exotegmic); (endosperm starchy); n = 9, 15, 16.

11/225: Asplundia (100), Dicranopygium (50), Sphaeradenia (50). Central and tropical South America, the Greater Antilles. [Photo - Flower, Fruit.]

• Cyclanthaceae are more or less herbaceous and have large, petiolate, plicate, toothed and/or deeply-divided leaves. The inflorescence is spadiciform and the flowers have a more or less inferior ovary. Cyclanthus itself can be recognised by its bifid leaves (or there is a bifid midrib) and distinctive spadix with spirally-arranged flowers. Although Cyclanthaceae can be confused with palms, their petioles are usually notably softer than those of palms and may be rounded.

Crown group Cyclanthaceae may diverge ca 77 million years before present (Janssen & Bremer 2004).

The subfleshy infructescences of genera like Carludovica open irregularly from the apex as the outer part of the infructescence recurves and pulls away, exposing the brightly-coloured interior.

In staminate flowers, both perianth and stamen number may increase. There is considerable variation in pollen morphology and seed morphology and anatomy.

For information on morphology and vernation of leaves, see Wilder (1981a, b), for growth habit, see Wilder (1992), for a detailed morphological phylogeny of the family, see Eriksson (1994), and for general information, see Harling (1958) and Harling et al. (1998).