LIGNOPHYTA

Plant a shrub or tree; true roots +, origin endogeneous, root cap +, apex multicellular; endodermis +; shoot apical meristem multicellular; lateral meristems +, cork cambium producing cork abaxially, vascular cambium producing phloem abaxially and xylem adaxially; lamina with mean venation density 1.8 mm/mm2 (to 5 mm/mm2).

EXTANT SEED PLANTS/SPERMATOPHYTA

Plant woody, evergreen; nicotinic acid metabolised to trigonelline, (cyanogenesis via tyrosine pathway); primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins derived from (some) sinapyl and particularly coniferyl alcohols, thus containing p-hydroxyphenyl and guaiacyl lignin units, so no Maüle reaction; root xylem exarch, cork cambium deep seated; arbuscular mycorrhizae +; shoot apical meristem interface specific plasmodesmatal network; stem with vascular tissue around central pith [eustele], vascular bundles with interfascicular tissue, ectophloic, endodermis 0, xylem endarch; wood homoxylous, tracheids and rays alone, tracheid/tracheid pits circular, bordered; mature sieve tube/cell lacking functioning nucleus, sieve tube plastids with starch grains; phloem fibres +; stem cork cambium superficial; branches exogenous; leaves with single trace from vascular sympodium ["nodes 1:1"]; vascular bundles collateral [stem: phloem external; leaf: phloem abaxial]; stomata morphology?, pore opening controlled by abscisic acid; leaves with petiole and lamina, spiral, development basipetal, blade simple; axillary buds +, not associated with all leaves; prophylls two, lateral; plant heterosporous, sporangia borne on sporophylls; microsporophylls aggregated in indeterminate cones/strobili; true pollen +, grains mono[ana]sulcate, exine and intine homogeneous; ovules unitegmic, parietal tissue 2+ cells across, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development first endo- then exosporic, tube developing from distal end of grain, to ca 2 mm from receptive surface to egg, gametes two, developing after pollination, with cell walls, flagellae numerous; ovules increasing considerably in size between pollination and fertilization, female gametophyte endosporic, initially syncytial, walls then surrounding individual nuclei; seeds "large" [ca 8 mm3], but not much bigger than ovule, with morphological dormancy; embryo cellular ab initio, endoscopic, plane of first cleavage of zygote transverse, suspensor +, short-minute, embryo straight, shoot and root at opposite ends [allorrhizic], white, cotyledons 2; plastid transmission maternal; ycf2 gene in inverted repeat, two copies of LEAFY gene, PHY gene duplications [three - [BP [A/N + C/O]] - copies], nrDNA with 5.8S and 5S rDNA in separate clusters; mitochondrial nad1 intron 2 and coxIIi3 intron and trans-spliced introns present.

MAGNOLIOPHYTA

Lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, non-hydrolysable tannins, quercetin and/or kaempferol +, apigenin and/or luteolin scattered, [cyanogenesis in ANITA grade?], S [syringyl] lignin units common, positive Maüle reaction [syringyl:guaiacyl ratio more than 2-2.5:1], and hemicelluloses as xyloglucans; root apical meristem intermediate-open; root vascular tissue oligarch [di- to pentarch], lateral roots arise opposite or immediately to the side of [when diarch] xylem poles; origin of epidermis with no clear pattern [probably from inner layer of root cap], trichoblasts [differentiated root hair-forming cells] 0, exodermis +; shoot apex with tunica-corpus construction, tunica 2-layered; reaction wood ?, associated gelatinous fibres [g-fibres] with innermost layer of secondary cell wall rich in cellulose and poor in lignin; starch grains simple; primary cell wall mostly with pectic polysaccharides, poor in mannans; tracheid:tracheid [end wall] plates with scalariform pitting, wood parenchyma +; sieve tubes enucleate, sieve plate with pores (0.1-)0.5-10< µm across, cytoplasm with P-proteins, cytoplasm not occluding pores of sieve plate, companion cell and sieve tube from same mother cell; sugar transport in phloem passive; nodes unilacunar [1:?]; stomata brachyparacytic [ends of subsidiary cells level with ends of pore], outer stomatal ledges producing vestibule; lamina formed from the primordial leaf apex, margins toothed, development of venation acropetal, secondary veins pinnate, overall growth ± diffuse, venation hierarchical, fine venation reticulate, veins (1.7-)4.1(-5.7) mm/mm2, endings free; most/all leaves with axillary buds; flowers perfect, pedicellate, ± haplomorphic, parts spiral [esp. the A], free, numbers unstable, development in general centripetal; P not sharply differentiated, with a single trace, outer members not enclosing the rest of the bud, often smaller than inner members; A many, filament not sharply distinguished from anther, stout, broad, with a single trace, anther introrse, tetrasporangiate, sporangia in two groups of two [dithecal], ± embedded in the filament, with at least outer secondary parietal cells dividing, each theca dehiscing longitudinally, endothecium +, endothecial cells elongated at right angles to long axis of anther; tapetum glandular, cells binucleate; microspore mother cells in a block, microsporogenesis successive, walls developing by centripetal furrowing; pollen subspherical, tectum continuous or microperforate, ektexine columellar, endexine thin, compact, lamellate only in the apertural regions; nectary 0; G superior, free, several, ascidiate, with postgenital occlusion by secretion, stylulus short, hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, dry [not secretory]; ovules few [?1]/carpel, marginal, anatropous, bitegmic, micropyle endostomal, outer integument 2-3 cells across, often largely subdermal in origin, inner integument 2-3 cells across, often dermal in origin, parietal tissue 1-3 cells across [crassinucellate], nucellar cap?; megasporocyte single, hypodermal, megaspore tetrad linear, functional megaspore chalazal, lacking sporopollenin and cuticle; female gametophyte four-celled [one module, nucleus of egg cell sister to one of the polar nuclei]; ovule not increasing in size between pollination and fertilization; pollen binucleate at dispersal, male gametophyte trinucleate, germinating in less than 3 hours, pollination siphonogamous, tube elongated, growing between cells, growth rate 20-20,000 µm/hour, outer wall pectic, inner wall callose, with callose plugs, penetration of ovules via micropyle [porogamous], whole process takes ca 18 hours, distance to first ovule 1.1-2.1 mm; male gametes lacking cell walls, flagellae 0, double fertilization +, ovules aborting unless fertilized; P deciduous in fruit; seed exotestal, becoming much larger than ovule at time of fertilization; endosperm diploid, cellular [micropylar and chalazal domains develop differently, first division oblique, micropylar end initially with a single large cell, divisions uniseriate, chalazal cell smaller, divisions in several planes], copious, oily and/or proteinaceous; embryogenesis cellular; germination hypogeal, seedlings/young plants sympodial; Arabidopsis-type telomeres [(TTTAGGG)n]; whole genome duplication, ndhB gene 21 codons enlarged at the 5' end, single copy of LEAFY and RPB2 gene, knox genes extensively duplicated [A1-A4], AP1/FUL gene, paleo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and three copies of the PHY gene, [PHYB [PHYA + PHYC]].

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

[AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]: essential oils in specialized cells [lamina and P ± pellucid-punctate]; tension wood 0; tectum reticulate; anther wall with outer secondary parietal cell layer dividing; carpels plicate; nucellar cap + [character lost where in eudicots?]; 12BP [4 amino acids] deletion in P1 gene.

[[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]] / MESANGIOSPERMAE: benzylisoquinoline alkaloids +; polyacetate derived anthraquinones + [?level]; outer epidermal walls of root elongation zone with cellulose fibrils oriented transverse to root axis; P more or less whorled, 3-merous [possible positiion]; embryo sac bipolar, 8 nucleate, antipodal cells persisting; endosperm triploid; ?germination.

[MONOCOTS [CERATOPHYLLALES + EUDICOTS]]: (veins in lamina often 7-17mm/mm2 or more [mean for eudicots 8.0]); (stamens opposite [two whorls of] P); (pollen tube growth fast).

MONOCOTYLEDONS / MONOCOTYLEDONEAE / LILIANAE Takhtajan

Plant herbaceous, perennial, rhizomatous, growth sympodial; non-hydrolyzable tannins [(ent-)epicatechin-4] +, neolignans, benzylisoquinoline alkaloids 0, hemicelluloses as xylans; root apical meristem?; root epidermis developed from outer layer of cortex; trichoblast in atrichoblast [larger cell]/trichoblast cell pair further from apical meristem, in vertical files, or hypodermal cells dimorphic; endodermal cells with U-shaped thickenings; cork cambium in root [uncommon] superficial; root vascular tissue oligo- to polyarch, medullated, lateral roots arise opposite phloem poles; primary thickening meristem +; vascular bundles in stem scattered, (amphivasal), closed, vascular cambium 0; vessel elements in root with scalariform and/or simple perforations; tracheids only in stems and leaves; sieve tube plastids with cuneate protein crystals alone; stomata parallel to the long axis of the leaf, in lines, brachyparacytic; leaves with broad sheath plus blade [not petiole plus lamina], blade linear, main venation parallel, veins joining successively from the outside at the apex, endings not free, margins entire, (teeth spiny), Vorläuferspitze +, leaf base sheathing, sheath open, colleters [intravaginal squamules] +; prophyll single, adaxial; inflorescence terminal, racemose; flowers 3-merous [6-merous to the pollinator?], polysymmetric, pentacyclic; P = T, each member with three traces, median member of outer whorl abaxial, aestivation open, members of whorls alternating, similar, [pseudomonocyclic, each providing a sector for the T tube when present]; stamens = and opposite each T member [primordia often associated, and/or A vascularized from tepal trace], anther and filament more or less sharply distinguished, anthers subbasifixed, endothecium from outer secondary parietal cell layer, inner secondary parietal cell layer dividing; G [3], with congenital intercarpellary fusion, opposite outer tepals [thus median member abaxial], placentation axile; ovule with outer integument often largely dermal in origin, parietal tissue 1 cell across; antipodal cells persistent, proliferating; fruit a loculicidal capsule; seed testal; endosperm with distinct nuclear and chalazal chambers, embryo long, cylindrical, cotyledon 1, apparently terminal, plumule apparently lateral; primary root unbranched, not very well developed, "adventitious" roots numerous, hypocotyl short, (collar rhizoids +), cotyledon with a closed sheath, unifacial [hyperphyllar], both assimilating and haustorial; duplication producing monocot LOFSEP and FUL3 genes, [latter duplication of AP1/FUL gene], PHYE gene lost.

[ALISMATALES [PETROSAVIALES [[DIOSCOREALES + PANDANALES] [LILIALES [ASPARAGALES + COMMELINIDS]]]]]: ethereal oils 0; raphides + (druses 0); leaf blade vernation variants of supervolute-curved; endothecium develops directly from undivided outer secondary parietal cells; tectum reticulate with finer sculpture at the ends of the grain, endexine 0; (septal nectaries + [intercarpellary fusion postgenital]).

[PETROSAVIALES [[DIOSCOREALES + PANDANALES] [LILIALES [ASPARAGALES + COMMELINIDS]]]]: cyanogenic glycosides uncommon; starch grains simple, amylophobic; leaf blade developing basipetally from hyperphyll/hypophyll junction; epidermis with bulliform cellls [?level]; stomata anomocytic, (cuticular waxes as parallel platelets); colleters 0.

[[DIOSCOREALES + PANDANALES] [LILIALES [ASPARAGALES + COMMELINIDS]]]: nucellar cap 0; endosperm nuclear [but variation in most orders].

[LILIALES [ASPARAGALES + COMMELINIDS]]: (inflorescence branches cymose).

[ASPARAGALES + COMMELINIDS]: style long.

COMMELINIDS: Unlignified cell walls with UV-fluorescent ferulic and coumaric acids; (vessels in stem and leaves); SiO2 bodies +, in leaf bundle sheaths; stomata para- or tetracytic, (cuticular waxes as aggregated rodlets [looking like a scallop of butter]); inflorescence branches determinate, peduncle bracteate; T = calyx + corolla [stamens adnate to corolla/inner whorl]; pollen starchy; embryo short, broad.

Phylogeny. Relationships of the main groups within commelinids are unclear; for further information, see discussion preceding Dasypogonaceae, also Zingiberales and Poales.

[POALES [COMMELINALES + ZINGIBERALES]]: primary cell wall mostly with glucurono-arabinoxylans; stomata subsidiary cells with parallel cell divisions; endosperm reserves starchy.

[COMMELINALES + ZINGIBERALES]: inflorescences with many-flowered cincinnal branches [helicoid cymes]; tapetum invasive or plasmodial.   Back to Main Tree

Evolution. Divergence & Distribution. The stem group dates to ca 116 m.y., divergence of the two clades to ca 114 m.y.(Janssen & Bremer 2004), while the figures in Wikström et al. (2001) are 87-83 and 81-73 m.y. respectively (see also Wikström et al. 2004 for the latter age), and in Bremer (2000b: largely fossil calibrations) ca 108 m.y. and ca 84 m.y. respectively. More recent dates in Kress and Specht (2006) are ca 124 (stem group) and 110-80 (divergence) m.y. while Magallón and Castillo (2009) estimate ca 109.7 and 99.9 m.y. for relaxed and constrained penalized likelihood datings for the stem group.

Monosymmetric flowers in this clade, especially in Zingiberales and Haemodoraceae, have a variety of very different morphologies; for monosymmetry, see Rudall and Bateman (2004). Indeed, monosymmetric flowers can be optimised to this node, as by Endress (2011a), who suggested that it might be a key innovation here. Enantiostyly is also common.

Chemistry, Morphology, etc. For monosymmetry, see Rudall and Bateman (2004). Tapetal variation in those few Zingiberales studied is extensive (Prakash et al. 2000; Furness & Rudall 2001; Simão et al. 2007).

Phylogeny. In previous studies this group has sometimes been rather weakly supported (e.g. Chase et al. 2000a; Davis et al. 2004: Givnish et al. 2006b, one gene), although it has 100% support in the multi-gene analysis of S. W. Graham et al. (2006) and Chase et al. (2006) and good support in the multigene (but poor sampling) study of Soltis et al. (2011). In some individual analyses in Davis et al. (2004) Commeliaceae were paraphyletic and included Zingiberaceae.

COMMELINALES Dumortier  Main Tree, Synapomorphies.

Mycorrhizae absent; (phenyphenalenones +); vessel elements with scalariform perforation plates; cuticle waxes not as aggregated rodlets; (flower enantiostylous); seed coat testal and tegmic; endosperm abundant, helobial, cell wall formation in small chalazal chamber precedes that in large micropylar chamber; collar rhizoids +. - 5 families, 68 genera, 812 species.

Note: Possible apomorphies are now being added throughout the site; they are in bold. However, the actual level at which many of these features, particularly the more cryptic ones, should be assigned is unclear. This is because there is very considerable homoplasy, with variation within and between clades, for most characters. Furthermore, the basic information for all too many characters is very incomplete, often coming from taxa well embedded in the clade of interest and so making the position of any putative apomorphy uncertain. Then there is the not-so-trivial issue of how ancestral states are reconstructed...

Evolution. Divergence & Distribution. Stem-group Commelinales are dated to ca 114 m.y. before present, divergence within the group to ca 110 m.y. before present (Janssen & Bremer 2004); the corresponding dates in Wikström et al. (2001) are 81-73 and 71-66 m.y. before present respectively. Magallón and Castillo (2009: no crown group ages) estimate ca 110 and 99 m.y. for relaxed and constrained penalized likelihood datings for the stem group.

Chemistry, Morphology, etc. For phenyphenalenones, see Otálvaro et al. (2002). Tapetal raphides are known from Commelinaceae, Philydraceae and Haemodoraceae, but their general distribution is unclear (Hardy & Stevenson 2000; Prychid et al. 2003a); there may be systematically interesting variation in the pattern of endothecial thickenings (Manning 1996). A five base pair insertion in the matK gene in members of Hanguanaceae and Pontederiaceae was found by Tamura et al. (2004a), it was absent in Haemodoraceae, but no other taxa were sampled. For monosymmetry, see Rudall and Bateman (2004).

Phylogeny. For relationships, see Hopper et al. (1999), S. W. Graham et al. (2006), Chase et al. (2006) and Saarela et al. (2008). Graham (in Graham et al. 2002) noted that there was very strong support for the grouping [Haemodoraceae + Pontederiaceae]. Janssen and Bremer (2004) suggest a rather different - and perhaps unlikely - set of relationships - [Philydraceae [Hanguanaceae [Haemodoraceae [Commelinaceae + Pontederiaceae]]]], and the dates here are based on this topology; Givnish et al. (2006b: ndhF gene only) also found Philydraceae to be sister to other Commelinales, but the position had little support, while Davis et al. (2004; see also Chase et al. 2000) found a clade [Hanguanaceae [Commelinaceae + Pontederiaceae]].

There has been much discussion over the position of Hanguanaceae in particular, which in morphological analyses tends to cluster - sometimes quite strongly (Rudall et al. 1999) - with Zingiberales, although it lacks the inferior ovary of members of that order. Molecular analyses suggest the inclusion of Hanguanaceae in Commelinales, and Givnish et al. (1999: rbcL analysis) found that Hanguanaceae were sister to Commelinaceae (see also Tillich 1997).



Includes Commelinaceae, Haemodoraceae, Hanguanaceae, Philydraceae, Pontederiaceae.

Synonymy: Haemodorales Martius, Hanguanales Reveal, Philydrales Dumortier, Pontederiales Martius

[Hanguanaceae + Commelinaceae]: stem above ground; cotyledon not photosynthetic.

HANGUANACEAE Airy Shaw   Back to Commelinales

Hanguanaceae

Mucilage canals +; hairs multicellular, branched; epicuticular waxes 0; leaves spiral, with petiole, midrib and cross veins; plant dioecious; inflorescence branched-spicate, flowers sessile; T small; staminate flowers: stamens = and opposite each T member, filaments broadened and connate at very base; ?tapetum; pollen inaperturate, exine spinulose; pistillode +; carpellate flowers: staminodes nectar-secreting; G with intra-ovarian trichomes, mucilage-producing, style ± 0, stigmas 3; ovule 1/carpel, basal, straight, micropyle?, parietal tissue absent, epidermal cells anticlinally elongated, suprachalazal zone massive; fruit a 1-seeded berry; seed bowl-shaped [placenta inside the bowl!]; testa ca 5 cells across, endotesta with inner periclinal walls thickened, tegmen with two layers of crossing fibres; endosperm type?, embryo small; n = ca 24, 36, 45, chromosomes 1> µm long; primary root well developed.

1[list]/10. Sri Lanka, South East Asia to Palau and N. Australia (map: see Hewson 1986). [Photo - Fruit]

Evolution. Divergence & Distribution. Hanguanaceae diverged from other Commelinales ca 104 m.y. before present (Janssen & Bremer 2004).

Chemistry, Morphology, etc. Raphides may occur, but they are rare (Prychid & Rudall 1999). In Takhtajan (1985) there are illustrations of a several-layered testa and a massively-thickened tegmen with crossing fibres. However, Tillich (1996b) described the seed coat as being testal - but his outer layer seems comparable to Takhtajan's endotesta and his inner layer to one of the tegmic layers...

Additional information is taken from Tillich (1996b: seedling), Bayer et al. (1998b: general), Tillich and Sill (1999: general), Givnish et al. (1999: rbcL), and Rudall et al. (1999: a great deal).

Previous Relationships. Hanguana was often included in Flagellariaceae (now in Poales), while more recent morphological studies have linked them with Zingiberales (see above).

COMMELINACEAE Mirbel, nom. cons.   Back to Commelinales

6-hydroxyflavonoids +; vessels also in stem; raphide canals; hairs uniseriate; stem with swollen nodes; (prophylls lateral); leaves spiral (two-ranked), midrib prominent, sheath closed; andromonoecy common; inflorescences axillary (terminal), (boat-like bracts conspicuous); flowers open one day; P differentiated, = K + C, C deliquescent; (G [2]), septal nectaries 0; micropyle (exo)/endostomal (micropyle naked), outer integument 3-7(-10) cells across, inner 2, (parietal tissue absent, or -2 cells across), nucellar cap to 2 cells across; fruit a loculicidal capsule, endocarp with fibres in vertical series, transversely elongated, variously thickened; (seeds uniseriate); exotesta thin, endotesta silicified, operculum + ["embryotega"] +; endosperm nuclear, chalazal haustorium +, embryo marginal, cotyledon ± lateral, suspensor 0; n = 4³; coleoptile +.

40[Genera List]/652. Tropical and temperate.[Photos - Collection.]

Cartonematoideae

Cartonematoideae G. C. Tucker

(annual; ?caespitose perennial, [bulbous]); SiO2 bodies 0; stem collenchyma 0; raphide canals next to veins or 0; stomata paracytic or tetracytic; glandular microhairs 0, although plant glandular pubescent; leaves long-linear; (inflorescence spicate), (leaf opposed, cymose); flowers ± sessile, median K adaxial [?Triceratella], C yellow; ?tapetum; ovule ?straight; operculum lacking collar, most of testa sloughed off; seedling collar short, mesocotyl +, primary root strong; n = 12.

2/12. Australasian, Triceratella (to be included?) Zimbabwe (map: from FloraBase ix.2010; Trop. Afr. Fl. Pl. Ecol. Distr. 7. 2012).

Synonymy: Cartonemataceae Pichon, nom. cons.

Commelinoideae Eaton

Commelinoideae

Rather succulent herbs; (mycorrhizae 0); cyanidin 3,7,3'-triglucoside +; stem collenchyma +; vessel elements with simple perforation plates, also in stem and leaf; stem with narrow cortex and endodermis-like sheath enclosing vascular bundles that connect only at the nodes; (SiO2 bodies +); raphide canals between veins; stomata tetracytic, etc.; 3-celled glandular microhairs +; (leaf vernation involute); (inflorescence axillary), (prophyll lateral); flowers with the median sepal adaxial, (obliquely monosymmetric [when monosymmetric, C often 2, adaxial members]), (enantiostylous); K/C, or T, 1- or 3- trace, blue, pink or white (yellow), (C tubular); A 1-6, (adnate to C), often variable in morphology, anthers poricidal, with 2+ fibrous middle layers, (connective [much] expanded), filaments often with dense uniseriate hairs, staminodes often 2-4, attractive; pollen with raphides; ovules >1/carpel, straight to campylotropous; (embryo sac bi- or tetrasporic, 8[haploid]-nucleate), (antipodal cells ± persisting - Tinantia), polar nuclei fuse early; (fruit a berry), (endocarp with cross-shaped - Forrestia); seed endotestal, (also exotegmic), operculum testal, with a micropylar collar; starch grains complex; n =4<, often "large".

38/640: Commelina (170), Tradescantia (70), Aneilema (68), Murdannia (50), Cyanotis (50). Tropical, also temperate, not Europe (map: see Heywood 1978; modified from Fl. N. Am. 22: 2000; FloraBase 2004; Trop. Afr. Fl. Pl. Ecol. Distr. 7. 2012). [Photo - Flower, another Flower.]

Synonymy: Ephemeraceae Batsch, nom. rej., Tradescantiaceae Salisbury

Evolution. Divergence & Distribution. Stem group Commelinaceae are dated to ca 89 m.y., divergence within Commelinoideae to ca 62 m.y. (Janssen & Bremer 2004: Cartonematoideae not included, c.f. topology of the tree).

Chemistry, Morphology, etc. Remizowa et al. (2011) suggested that the apparently cymose part inflorescences of Tradescantia were in fact racemose, but c.f. e.g. Panigo et al. (2011). On the other hand, the apparently racemose inflorescences of Cartonema have been described as having one flower/cincinnus (Brenan 1966). Leaf-opposed inflorescences and axillary inflorescences that perforate the leaf sheath as they emerge (as in Buforestia) are known from the family.

Floral symmetry and basic construction is variable. Flowers may be monosymmetric by the corolla, one petal being much reduced in Commelina, or primarily by the androecium, and the expression of monosymmetry may change during the development of the flower (Hardy et al. 2004). In Dichorisandra the bracteoles are more or less lateral and the plane of symmetry of the flower is transverse, while in other taxa it is oblique (e.g. Eichler 1875); Preston and Hileman (2012) show most flowers of Commelinoideae as having an inverted orientation, and this is compatible with Eichler's suggestion. Interestingly, TB1-like genes, involved in the development of monosymmetry elsewhere in monocots and eudicots, are not expresssed in the sepal-like abaxial inner petal of Commelina communis, although they are in the other petals, stamens and staminodes; there is a similar pattern of expression of B-class DEF-like genes, not being expressed in the abaxial member of the petal whorl either (Preston & Hileman 2012). Cochliostemon has asymmetric flowers (Hardy & Stevenson 2000a for development). Enantiostyly occurs, but is uncommon. For expression (very little) of B-class genes (DEF) in the sepals of species that have them see Ochiai et al. (2004). Flowers may have tepals, the stamens being opposite the tepal members, or a calyx and corolla; the inner T/corolla members may have only a single trace. A floral tube may be formed by connation of the petals, as in Weldenia, or by adnation of alternating corolla and the filaments of the antisepalous stamens (Rohweder 1979b). Variation in androecial development is extreme, and in some taxa androecial development has been reported as being centrifugal, perhaps a variant of obdiplostemony (Hardy & Stevenson 2000b; Hardy & Ryndock 2012, but see Endress 2010d).

Indehiscent geocarpic fruits may be produced by Commelina bengalensis and Tapheocarpa. Mabberley (1987) suggested that some taxa may have a small second cotyledon, but to what structure this might refer is unclear. Tillich (1996a [check]) described the cotyledon as being of the dropper type. Seedling leaves and often those at the base of axillary shoots are often two-ranked even in those taxa that have spiral leaves predominating in the vegetative plant.

Some information is taken from Rohweder (1963, 1970b), Faden and Hunt (1991), and Faden (1998), all general, Maheshwari and Baldev (1959) and Chikkmannaiah (1963 and references), both embryology, Tomlinson (1966: anatomy), Jones and Jopling (1972: cytology), Stirton and Harborne (1980: anthocyanins - see cyanidin 3,7,3'-triglucoside distribution, Cartonematoideae not sampled), MartÍnez and Swain (1985: flavonoids), Hardy et al. (2000b, 2004: floral development), Evans et al. (2000: stomatal development), Choob and Mavrodiev (2001: prophylls, etc), Hofreiter and Tillich (2002: root anatomy, quite a bit of variation), Burns et al. (2008: vegetative morphology) and Calderón et al. (2009: ecdysteroids).

Phylogeny. A morphological phylogeny shows little resolution, although anatomical characters gave significantly more support for a rbcL phylogeny than did other kinds of characters (Evans et al. 2000, c.f. Evans et al. 2003). In morphological studies, most taxa with strongly monosymmetric flowers form a clade; Triceratella is widely separated from Cartonema, but the latter is sister to the rest of the family. Givnish (2003, summary tree only, no support values) emphasized that morphological data did not retrieve a monophyletic Commelineae and Tradescantieae largely because of high homoplasy of androecial characters, while molecular (rbcL) data did find these tribes to be monophyletic (with the exception of Floscopa, see below; Calisia [Tradescantieae] had a similarly isolated position in the morphological analyses). Evans et al. (2003: rbcL phylogeny, Triceratella not studied) also note conflict between morphology and molecules.

Within Commelinoideae, Commelineae and Tradescantieae are monophyletic, with Floscopa (chromosomes 3³ µm long), previously included in Tradescantieae, as sister to both (Givnish 2003). Commelineae have stomata with 6 subsidiary cells, spiny pollen and chromosomes ca 1-5 µm long; monosymmetric flowers are commonest here and anther hairs, if present, are not moniliform. Tradescantieae have stomata with 2-6 subsidiary cells, moniliform hairs and chromosomes ca 2-10 µm long (c.f. Judd et al. 2002); flowers with tepals (i.e. not differentiated into sepals and petals) are commonest in this clade. Wade et al. (2006) carried out a two-gene analysis of Tradescantieae; the position of Palisota is still unresolved. Burns et al. (2011), in an extensive analysis of Commelinoideae (no Cartonematoideae included), found Commelineae and Tradescantieae to be moderately supported, with Palisota and Spatholirion successive sister taxa to Commelineae (moderate support). Callisia (Tradescantieae) is para/polyphyletic. Spalink et al. (2009) outlined relationships in Aneilema.

Classification. Wade et al. (2006) provide a subtribal classification of Tradescantieae; some subtribes are paraphyletic.

[Philydraceae [Haemodoraceae + Pontederiaceae]]: SiO2 bodies 0; styloids +; T with tannin cells; sclereids in placentae; T persistent in fruit.

PHILYDRACEAE Link, nom. cons.   Back to Commelinales

Philydraceae

Proanthocyanins +; stem vascular tissue various; (stomata tetracytic); hairs often wooly; leaves two-ranked, equitant and isobifacial [oriented edge on to the stem], terete [Philydrella]; groups of flowers [?arrangement] in axils of spathe-like bracts; flowers open for one day, enantiostylous; T whorls differentiated, both petal-like, 2 adaxial outer T plus adaxial inner T all fused, abaxial outer T, large, free, inner T 2, lateral, small, adnate to A (not - Helmholtzia); A 1, [median member of outer whorl], (anther coiled); tapetum secretory; pollen with raphides, (in tetrads); septal nectaries 0, (style impressed), stigma large; ovules many/carpel, integuments 1-2/2-3, (parietal tissue 2 cells across), ± postament, hyopostase, funicular obturator +; (seed with caruncle [from outer integument] and chalazal processes); exotesta with thick cellulose walls, (cells spiralling around seed), endotegmen tanniniferous, operculum tegmic; endosperm also with oil and crystalline aleurone bodies, chalazal haustorium +, chalazal chamber cellular ab initio, embryo long, suspensor hardly developed; n = 8, 16, 17; cotyledon linear, bifacial.

4[list]/5. Australia (all genera) to Southeast Asia (map: from Adams 1987; Hamann 1998b).

Evolution. Divergence & Distribution. Stem group Philydraceae are dated to ca 110 m.y., the crown group to ca 47 m.y. (Janssen & Bremer 2004). Philydrum languinosum is found throughout most of the range of the family; all other species have local distributions in New Guinea and Australia.

Chemistry, Morphology, etc. Information is taken from Malmanche (1919: anatomy), Kapil and Walia (1965: embryology of Philydrum), Tillich (1994: seedlings) and Hamann (1962b: endosperm, 1966: much detail, 1998: general).

Phylogeny. For phylogenetic relationships within Philydraceae, see Saarela et al. (2008); Philydrella is sister to the rest of the family.

[Haemodoraceae + Pontederiaceae]: phenylphenalenones +; endothecial cells with base-plates, ektexine not tectate or columellate.

Chemistry, Morphology, etc. For phenylphenalenones, see Otálvaro et al. (2002); these are phytoalexins with the formula (phenylphenalenone) of C19 H12 O, three six-C rings fused plus a benzene.

For the base plates of endothecial cells, see Manning (1996: not in Commelinaceae, other families unknown, sampling poor).

HAEMODORACEAE R. Brown, nom. cons.   Back to Commelinales

Haemodoraceae

(Plant cormose); fructans, chelidonic acid, flavones +; vessel elements in roots often with simple perforation plates, (vessels also in stem and leaf); leaves two-ranked, equitant and isobifacial, (margins [minutely] spiny); cyme [usu.] bifurcated, prophyll ± lateral; flowers (large), (monosymmetric), plane of symmetry transverse to oblique; (T tube +); A (connective appendages +); pollen with raphides; exine (1-)2(-3)-layered [no foot layer]; ovary inferior, placentae swollen; ovules 1-many/carpel, micropyle (exo)/endostomal, parietal tissue to 3 cells across, (nucellar cap +); cells of testa (and tegmen) variously elongated, ± thin-walled, operculum 0; chalazal endosperm haustorium +, embryo small/minute; ?collar rhizoids.

14[list]/116 - two subfamilies below. Tropics and warm temperate regions (map: from Heywood 1978 [Africa]; MacFarlane et al. 1987 [Australia]; Maas & Maas-van der Kamer 1993 [America]; Fl. N. Am. 26: 2002 [N. America]).

1. Haemodoroideae Arnott

(Plant bulbose), roots red; tannins 0; hairs with distinctive basal cells; flowers enantiostylous, tannin cells 0, usu. glabrous; A 3, opposite inner P, (1 - Pyrorrhiza; staminodes +); ovary superior (inferior); seeds often flattened, pubescent or marginally winged; cotyledon not photosynthetic, hypocotyl at most short; n = 12, 15, 19-21.

8/39: Haemodorum (20). Tropics and warm temperate regions, not in southern South America, in Africa, only southern, in S.E. Asia not W. of Wallace's Line. [Photo - Flower, Fruit, Flower]

Synonymy: Dilatridaceae M. Roemer, Wachendorfiaceae Herbert, Xiphidiaceae Dumortier

2. Conostylidoideae Lindley

SiO2 sand +; tannin-containing cells; (epidermal walls thickened), hairs branched; flowers usu. pubescent; P connate or not, (valvate; monosymmetric; stamens = and opposite each T member); (A adnate to P); pollen 2-8 porate; (ovary ± inferior; (fruit indehiscent or a schizocarp); (seeds ridged, tegmen massive - Anigozanthus); cotyledon photosynthetic, hypocotyl +, primary root well developed; n = 4-8, 11.

6/80: Conostylis (50). S.W. Australia. [Photo - Flower]

Synonymy: Conostylidaceae Takhtajan

Evolution. Divergence & Distribution. Stem group Haemodoraceae are dated to ca 98 m.y., divergence within the crown group to ca 81 m.y. (Janssen & Bremer 2004). Divergence within Haemodoroideae occurred in the early Eocene ca 47.9 m.y.a., that within Conostyloideae later in the Eocene ca 42 m.y.a. (Hopper et al. 2009). The restriction of Conostylidoideae to SW Australia is remarkable; Hopper et al. (2006) discuss the diversification of this group, in particular, that of Conostylis.

Plant-Animal Interactions. Bugs of the Hemiptera-Lygaeidae-Blissinae eat seeds of Haemodoroideae from South Africa; most bugs of this clade are sap-eaters (Slater 1976).

Chemistry, Morphology, etc. The median petal is abaxial in monosymmetric flowers of Haemodoroideae such as Wachendorfia, i.e., the flowers are inverted, while in Anigozanthus zygomorphy is evident as a slit down one side of a tube formed by the six connate tepals - the plane of symmetry must necessarily be slightly oblique here. As Eichler (1880) noted, if flowers are examined early in development, Wachendorfia has flowers with transverse symmetry, while in Anigozanthus they are oblique. Taxa like Xiphidium may have a more or less differentiated perianth with the two whorls each fully encircling the apex; the three stamens are borne opposite the petals/inner tepals. However, Anigozanthus clearly has six stamens individually opposite the six perianth lobes (see illustrations in Simpson 1990). There is clearly much variation in basic floral organization in this relatively small family.

The ovary may be secondarily superior (Simpson 1998a, b); the septal nectaries are found below the point of insertion of perianth. The outer periclinal wall of the testa is thick. Some additional information is taken from Simpson (1988, 1990); for variation in the pollen of Conostylis, see Pierce and Simpson (2009).

Phylogeny. The phylogeny of the family has been quite extensively studied and integrated with anatomical and morphological variation (Hopper et al. 1999; Simpson et al. 2006). For the phylogeny of Conostylidoideae, see Hopper et al. (2006).

PONTEDERIACEAE Kunth, nom. cons.   Back to Commelinales

Pontederiaceae

Water or marsh plants; vegetative stems indeterminate; (vessels also in stems); styloids or prismatic crystals 0 (+); stomatal subsidiary cells with oblique divisions; leaves spiral or spirally two-ranked (whorled), blade of leaf initially surrounding petiole of older leaf, petiolate or not, 2ndaries transverse, sheath open or closed, often long-ligulate [= "stipules" sheathing to minute], colleters +; inflorescence subtended by two bracts; flowers open for one day, tristyly, enantiostyly, monosymmetry all common; P = T, T ± undifferentiated, adaxial inner tepal with markings, (large), deliquescent, (4, 3), mostly blue or yellow, ± connate, (tube to 11 cm long); A adnate to T, (1, 3, 4; staminodes 2), of different lengths, (tapetum secretory), filaments hairy; pollen 2- or 3-sulcate; (septal nectaries 0); (1 carpel fertile), (placentation parietal), stigma small, dry; ovule (1/carpel), micropyle bistomal, parietal tissue absent (single layer - Monochoria), (epidermal cells ± radially elongated), postament +; (fruit an achene surrounded by P base); (seed ridged); exotestal cells box-like, endotestal cells elongated, tranversely flattened, operculum 0?; micropylar endosperm haustorium +, embryo long, suspensor hardly developed; n = (7) 8(-13); cotyledon linear, bifacial.

9[list]/33: Heteranthera (11). Tropics, also temperate, esp. New World (map: ; Fl. N. Am. 26: 2002). [Photos - Collection]

Evolution. Divergence & Distribution. Stem group Pontederiaceae are dated to ca 89 m.y., divergence within the crown group to ca 39 m.y. (Janssen & Bremer 2004).

Pollination Biology & Seed Dispersal. Considerable work has been carried out on the floral biology of Pontederiaceae, where tristyly, enantiomorphy and monosymmetry (and Pontederia cordata, at least, is obliquely monosymmetric) are all well known. Graham and Barrett (1995) discussed the evolution of the breeding system, while Barrett and Graham (1997) outlined the phylogeny and diversification of the family and Kohn et al. (1996) the evolution of reproductive features. However, there have been problems with rooting the phylogenetic tree (see below, also Ness et al. 2011 and references). In the enantiostylous Monochoria there are five small stamens with yellow anthers and one large stamen with a blue anther (Wang et al. 1995 for pollination). Lunau (2006) suggests that the yellowish spot on the median-adaxial tepal member of some other Pontederiaceae mimics a stamen.

Chemistry, Morphology, etc. In Heteranthera, Eichornia s. str. and Pontederia s. str. (at least) the blade of the first leaf of the axillary shoot completely encircles the main stem in bud, or the blade of the young leaf completely encircles the petiole of the next oldest leaf - this may be a unique arrangement (see also Eichler 1880). Although Hydrothrix gardneri appears to have whorled, linear leaves, only one leaf ateach node has a short, sheathing ligule; the others have narrower bases and are borne inside the sheath (Rutishauser 1999). Endothecial walls of Eichornia at least, have distinctive base-plate thickenings (Manning & Goldblatt 1990).

Information is taken from Coker (1907: seed anatomy), Ono (1928: ovule development), Tomlinson (1982: colleters), Tillich (1994: seedlings), Endress (1995b: flowers), Cook (1998: general) and Strange et al. (2004: floral anatomy).

Phylogeny. Eichornia currently is hopelessly paraphyletic, Pontederia and Monochoria being embedded in it (Graham et al. 1998; see also Ness et al. 2011). Simpson and Burton (2006) discuss the evolution of features of floral anatomy in the family, including outgroups; the embedded [Pontederia + Reussia] not only have single, apical ovules in the single fertile carpel and an achene surrounded by perianth, but they are the only members of the family to have styloids or prismatic crystals. Other features they studied also correlate with the clades evident in the phylogenetic analyses of Barrett and Graham (1997). There have been persistent problems in rooting the tree (also Graham et al. 1998, esp. 2002), but a recent study suggests that Eichornea meyeri is sister to the rest of the family - although there are still some lingering doubts (Ness et al. 2011).

Classification. Generic limits need attention.

Synonymy: Heterantheraceae J. Agardh