EXTANT SEED PLANTS

Plant woody, evergreen; nicotinic acid metabolised to trigonelline, (cyanogenesis via tyrosine pathway); primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins rich in guaiacyl units; true roots present, apex multicellular, xylem exarch, branching endogenous; arbuscular mycorrhizae +; shoot apical meristem multicellular, interface specific plasmodesmatal network; stem with ectophloic eustele, endodermis 0, xylem endarch, branching exogenous; vascular tissue in t.s. discontinuous by interfascicular regions; vascular cambium + [xylem ("wood") differentiating internally, phloem externally]; wood homoxylous, tracheids +; tracheid/tracheid pits circular, bordered; sieve tube/cell plastids with starch grains; phloem fibers +; stem cork cambium superficial, root cork cambium deep seated; nodes ?; stomata ?; leaf vascular bundles collateral; leaves spiral, simple, axillary buds?, prophylls [including bracteoles] two, lateral, veins -5 mm/mm² [mean for all non-angiosperms 1.8]; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores, i.e. no distal pore for release of gametes] +, grains mono[ana]sulcate, exine and intine homogeneous, ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development first endo- then exosporic, tube developing from distal end of grain, to ca 2 mm from receptive surface to egg, gametes two, with cell walls, with many flagellae; female gametophyte endosporic, initially syncytial, walls then surrounding individual nuclei; seeds "large", first cell wall of zygote transverse, embryo straight, endoscopic [suspensor +], short-minute, with morphological dormancy, white, cotyledons 2; plastid transmission maternal; two copies of LEAFY gene, PHY gene duplication [N/O//A/C and P//BE lines], mitochondrial nad1 intron 2 and coxIIi3 intron present.

MAGNOLIOPHYTA

Plant woody, evergreen; lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, non-hydrolysable tannins, quercetin and/or kaempferol +, apigenin and/or luteolin scattered, [cyanogenesis in ANITA grade?], lignins derived from both coniferyl and sinapyl alcohols, containing syringaldehyde [in positive Maüle reaction, syringyl:guaiacyl ratio less than 2-2.5:1], and hemicelluloses as xyloglucans; root apical meristem intermediate-open; root vascular tissue oligarch [di- to pentarch], lateral roots arise opposite or immediately to the side of [when diarch] xylem poles; origin of epidermis with no clear pattern [probably from inner layer of root cap], trichoblasts [differentiated root hair-forming cells] 0; stem with 2-layered tunica-corpus construction; wood fibers and wood parenchyma +; reaction wood ?, with gelatinous fibres; starch grains simple; primary cell wall mostly with pectic polysaccharides; tracheids +; sieve tubes eunucleate, with a sieve plate and cytoplasm with P-proteins, companion cells from same mother cell that gave rise to the sieve tube; nodes unilacunar [1:?]; stomata with ends of guard cells level with pore, paracytic, outer stomatal ledges producing vestibule; leaves with petiole and lamina [the latter formed from the primordial leaf apex], development of venation acropetal, 2ndary veins pinnate, fine venation reticulate, veins (1.7-)4.1(-5.7) mm/mm², endings free; flowers perfect, polysymmetric, parts spiral [esp. the A], free, development in general centripetal, numbers unstable; P not sharply differentiated, outer members not enclosing the rest of the bud, smaller than inner members; A many, with a single trace, introrse, filaments stout, anther ± embedded in the filament, tetrasporangiate, dithecal, with at least outer secondary parietal cells dividing, each theca dehiscing longitudinally by action of hypodermal endothecium, endothecial cells elongated at right angles to long axis of anther; tapetum glandular, binucleate; microspore mother cells in a block, microsporogenesis successive, walls developing by centripetal furrowing; pollen subspherical, binucleate at dispersal, trinucleate eventually, tectum continuous or microperforate, ektexine columellar, endexine thin, compact, lamellate only in the apertural regions; nectary 0; G free, several, ascidiate, with postgenital occlusion by secretion, few [?1] ovules/carpel, ovules marginal, anatropous, bitegmic, [outer integument often largely subdermal in origin, inner integument dermal], micropyle endostomal, integuments 2-3 cells thick, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte four-celled [one-modular, nucleus of egg cell sister to one of the polar nuclei], stylulus short, hollow, stigma ± decurrent, dry [not secretory]; P deciduous in fruit; seed exotestal; pollen germinating in less than 3 hours, tube elongated, growing at 80-600 µm/hour, with callose plugs and callose-based walls, penetrating between cells, siphonogamy, penetration of ovules within ca 18 hours, distance to first ovule 1.1.-2.1 mm; double fertilisation +, endosperm diploid, cellular [first division oblique, micropylar end initially with a single large cell, chalazal end more actively dividing], copious, oily and/or proteinaceous, embryo cellular ab initio, minute; germination hypogeal, seedlings/young plants sympodial; Arabidopsis-type telomeres [(TTTAGGG)_n]; whole genome duplication, single copy of LEAFY and RPB2 gene, knox genes extensively duplicated [A1-A4], AP1/FUL gene, paleo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and PHYA + C/PHYB + E gene pairs.

Evolution. Possible apomorphies for flowering plants are in bold. Note that the actual level to which many of these features, particularly the more cryptic ones, should be assigned is unclear, because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied, there is considerable variation between families in particular for several of these characters, and also because details of relationships among gymnosperms will affect the level at which some of these characters are pegged. For example, if reticulate-perforate pollen is optimized to the next node on the tree (see Friis et al. 2009 for a discussion), it effectively makes the pollen morphology of the common ancestor of all angiosperms ambiguous....

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

Phylogeny. For discussion 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.

Evolution. 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).

Chemistry, Morphology, etc. Stevenson et al. (2000) suggest other possible characters for the order and groups of families within it. These include a 6 bp deletion in atpA - absent in Talbotia (Velloziaceae), whether or nor it occurs in Barbaceniopsis is unclear (cf. Davis et al. 2004) - and a distinctively connate androecium; tenuinucellate ovules may be another synapomorphy, and starchy endosperm is common in the order. Rudall et al. (2005b) note that floral merism, usually not very variable in the monocots, varies considerably in Padanales; floral construction as a whole is rather labile in this order.

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

Phylogeny. This grouping of families is somewhat unexpected. However, Triuridaceae have often been grouped with Pandanales in molecular analyses (Chase et al. 2000a: only 18S rDNA examined) and Graham et al. (2005), although they were sometimes found to be sister to Zingiberaceae in some analyses by Davis et al. (2004 - an unlikely position, if morphology means anything!), if more frequently placed within Pandanales, but varying in their relationships there. Furthermore, Nartheciaceae have sometimes 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 (50³%, 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.

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 1³ µm across; stomata paracytic; P large, A bisporangiate/monothecal, pollen bi- or trinucleate, ovary inferior, many tenuinucellate ovules/carpel, style long; endosperm with starch.

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

1. Acanthochlamydoideae P. C. Kao

Caespitose rhizomatous herb; steroidal saponins +?; vessels also in stem and leaf, elements with simple perforation plates; 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; ?fruit; 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]

Synonymy: Acanthochlamydaceae P. C. Kao

2. Vellozioideae Rendle

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; median T in outer whorl adaxial [e.g. Barbacenia}, 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; fruit capsules poricidal, loculicidal, or with intercostal apertures; 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). [Photo - Habit, Flower.]

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.

Evolution. 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 (see Naidoo et al. 2009 for Xerophyta viscosa, also analysis of substances secreted on adaxial surface of the leaf). 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).

Chemistry, Morphology, etc. 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.

The roots of Acanthochlamys 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.

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: general) and Strassburg and de Menezes (2001: development).

Phylogeny. 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 the rest of the family (Behnke et al. 2000; Mello-Silva 2005).

Classification. Even if Acanthochalmys is sister to the rest of the family it is morphologically and anatomically rather different from them (Behnke et al. 2000; Mello-Silva 2005).

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

TRIURIDACEAE Gardner, nom. cons.   Back to Pandanales

Echlorophyllous mycoheterotrophic herbs; chemistry?; root hairs 0 (few); vessels 0; stem with a ring of bundles (endodermis +); crystals 0; plant glabrous; cuticular waxes as parallel platelets; stomata 0; leaves spiral, (base sheathing; closed); plant usu. mono- or dioecious, inflorescence a raceme, bracteole 0; (flowers monosymmetric), T with median member of outer whorl adaxial [?always], 3, 6 (4-10), valvate, ± connate; A 3, monothecal, or 6, dithecal, (2-8), extrorse to introrse, connate or not, filaments thick, (dehiscing by apical slits); tapetum cells uninuclear, (plasmodial - Sciaphilieae); pollen trinucleate, inaperturate, (monosulcate - Sciaphila), surface gemmate, gemmae with protruberances or spines; G 10-many, centrifugal, (fasciculate), plicate, 1 (2 - Kupea) basal tenuinucellate ovule/carpel, nucellar cap 0, endothelium +, styles (basal), solid, ?no transmitting tissue, 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.

Evolution. 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 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), recent work by Ambrose et al. (2006) suggests that heterotopy is a more likely explanation.

Lacandonia can self pollinate: Pollen grains germinate while still in the anther and the tubes grow through the tissue of the flower to the ovule (Márquez-Guzmán et al. 1989). In general, polllination by small flies is likely (Rudall & Bateman 2006).

Chemistry, Morphology, etc. The roots lack pith (von Guttenberg 1968) and the root stele is monarch or diarch; mycorrhizae are of the Paris type (Imhoff 1998). Staminate and carpellate flowers usually lack rudiments of pistils and stamens respectively. The clearly separate and numerous carpels represent a reversion. In the perfect flowers of Lacandonia and carpellate flowers of Triuris individual carpel primordia develop from compound primordia, and in the former stamen and carpel primordia develop from a common precursor. Rudall (2008) suggests that the basic construction of the gynoecium in at least some Triuridaceae is fasciculate, the fascicles being radially elongated. 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).

Phylogeny. 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 of Lacandonia becomes very specific indeed.

Previous Relationships. Triuridaceae have often been associated with Alismataceae and relatives, all having separate carpels and so assumed to be primitive.

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; vessel elements with scalariform perforation plates also in stem; petiole bundles in arc; (styloids +); hairs 0; leaves two-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.

Evolution. 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).

At least some Stemonaceae are pollen flowers (Vogel 1981).

Chemistry, Morphology, etc. 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. Duyfjes (1992) inadvertently suggested that Stemonaceae s. str. - i.e. not including Pentastemona - 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.

Pentastemona can be briefly characterised as follows: Succulent monopodial herb; 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, ovary inferior, placentation parietal, many ovules/carpel, stigmatic lobes well developed; fruit a berry; seed arillate; sarcoexotesta +, endotesta with massive U-shaped thickenings; seedling?

Additional 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).

Phylogeny. Pentastemona appears to be well embedded within the family (e.g. Jiang et al. 2006, molecular data, but cf. Rudall & Bateman 2006, morphological analysis).

Synonymy: Croomiaceae Nakai, Pentastemonaceae Duyfjes, Roxburghiaceae Wallich

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

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

Chemistry, Morphology, etc. The compound vascular bundles can sometimes be seen under a hand lens; the vascular bundles have groups of vessels at opposite ends with smaller cells in between. There are vessels in the leaves in Pandanaceae, but not in Cyclanthaceae.

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

Previous relationships. An odd group recognised in the past was the Spadiciflorae, a group that included those taxa with a spadix and often also a spathe, i.e. Pandanaceae, Cyclanthaceae, Araceae and Arecaceae; these families are now placed in three orders, Pandanales, Alismatales and Arecales.

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.

Evolution. 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)!

Chemistry, Morphology, etc. 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 carpels vary from free to variously connate and fasciate, and their orientation varies from centripetal to centrifugal (cf. Cercidiphyllum!), sometimes within a single floral unit (Stone 1968). 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), and Huynh (2001: Sararanga).

Phylogeny. For the phylogeny of the family, see Callmander et al. (2003).

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; fossil Cyclanthus [blue] from Smith et al. 2009).[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: G with ovary cavity with closely-set placentae; ovules lacking nucellar cap, funicles long; fruit dry, syncarpous, carpellary annulus sliding off the inflorescence axis and splitting down the middle; seeds ridged, embedded in mucilage; endotestal cells palisade, inner periclinal walls granular; 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 (two-ranked), 1- or 3-costate; inflorescences (axillary), flowers in spirals; staminate flowers: P in one (two) whorls, 6+ (-30), with abaxial gland (none); 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.

Evolution. Crown group Cyclanthaceae may begin to diverge ca 77 million years before present (Janssen & Bremer 2004). Cyclanthus has recently been identified from the European Eocene (seeds had previously been misidentified as a Scirpus), where it may even be a diagnostic element of the vegetation - along with Nypa (Smith et al. 2008).

Carludovicia is associated with derelomine flower weevils the adults of which pollinate the flowers while the larvae eat the developing seeds (Franz 2004). The fruits of Carludovicioideae are baccate, syncarpous or not, and are apically circumscissile or have other unusual methods of opening. Dispersal is by animals. Thus 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.

Chemistry, Morphology, etc. In staminate flowers, both perianth and stamen number may increase. There is considerable variation in pollen morphology and seed morphology and anatomy; Furness and Rudall (2006) suggest that the pollen grains of Cyclanthaceae, alone in the order, lack endexine lamellae.

For information on morphology and vernation of leaves, see Wilder (1981a, b), for growth habit, see Wilder (1992), for seeds, see Smith et al. (2008), and for general information, see Harling (1958) and Harling et al. (1998).

Phylogeny. For a detailed morphological phylogeny of the family, see Eriksson (1994).