EMBRYOPSIDA Pirani & Prado
Gametophyte dominant, independent, multicellular, thalloid, with single-celled apical meristem, showing gravitropism; rhizoids +, unicellular; flavonoids + [absorbtion of UV radiation]; chloroplasts lacking pyrenoids; protoplasm dessication tolerant [plant poikilohydric]; cuticle +; cell walls with (1->4)-ß-D-glucans [xyloglucans], lignin +; several chloroplasts per cell; glycolate metabolism in leaf peroxisomes [glyoxysomes]; centrioles in vegetative cells 0, metaphase spindle anastral, predictive preprophase band of microtubules, phragmoplast + [cell wall deposition spreading from around the spindle fibres], plasmodesmata +; antheridia and archegonia jacketed, stalked; spermatogenous cells monoplastidic, centrioles develop de novo, associated with basal bodies of flagellae, multilayered structure +, proximal end of basal bodies lacking symmetry, stellate pattern associated with doublet tubules of transition zone; spermatozoids with a left-handed coil; male gametes with 2 lateral flagellae; oogamy; sporophyte dependent on gametophyte, embryo initially surrounded by haploid gametophytic tissue, plane of first division horizontal [with respect to long axis of archegonium/embryo sac], suspensor/foot +, cell walls with nacreous thickenings; sporophyte multicellular, with at least transient apical cell [?level], sporangium +, single, dehiscence longitudinal; meiosis sporic, monoplastidic, microtubule organizing centre associated with plastid, cytokinesis simultaneous, preceding nuclear division, sporocytes 4-lobed, with a quadripolar microtubule system; spores in tetrads, sporopollenin in the spore wall, wall with several trilamellar layers [white-line centred layers, i.e. walls multilamellate]; close association between the trnLUAA and trnFGAA genes on the chloroplast genome.
Many of the bolded characters in the characterization above are apomorphies of subsets of streptophytes along the lineage leading to the embryophytes, not apomorphies of crown-group embryophytes per se.
All groups below are crown groups, nearly all are extant; characters mentioned are those of the common ancestor of the group.
Abscisic acid, ?D-methionine +; sporangium with seta, seta developing from basal meristem [between epibasal and hypobasal cells], sporangial columella + [developing from endothecial cells]; stomata +, anomocytic, cell lineage that produces them with symmetric divisions [perigenous]; underlying similarities in the development of conducting tissue and in rhizoids/root hairs; spores trilete; polar transport of auxins and class 1 KNOX genes expressed in the sporangium alone; MIKC, MI*K*C* and class 1 and 2 KNOX genes, post-transcriptional editing of chloroplast genes; gain of three group II mitochondrial introns.
[Anthocerophyta + Polysporangiophyta]: archegonia embedded/sunken in the gametophyte; sporophyte long-lived, chlorophyllous; sporophyte-gametophyte junction interdigitate, sporophyte cells showing rhizoid-like behaviour.
Sporophyte branched, branching apical, dichotomous; sporangia several; spore walls not multilamellate [?here].
EXTANT TRACHEOPHYTA / VASCULAR PLANTS
Photosynthetic red light response; water content of protoplasm relatively stable [plant homoiohydric]; control of leaf hydration passive; (condensed or nonhydrolyzable tannins/proanthocyanidins +); sporophyte soon independent, dominant, with basipetal polar auxin transport; vascular tissue +, sieve cells + [nucleus degenerating], tracheids +, in both protoxylem and metaxylem; endodermis +; root xylem exarch [development centripetal]; stem with an apical cell; branching dichotomous; leaves spirally arranged, blades with mean venation density 1.8 mm/mm2 [to 5 mm/mm2]; sporangia adaxial on the sporophyll, derived from periclinal divisions of several epidermal cells, wall multilayered [eusporangium]; columella 0; tapetum glandular; gametophytes exosporic, green, photosynthetic; stellate pattern split between doublet and triplet regions of transition zone; placenta with single layer of transfer cells in both sporophytic and gametophytic generations, embryonic axis not straight [root lateral with respect to the longitudinal axis; plant homorhizic].[MONILOPHYTA + LIGNOPHYTA]
Branching ± indeterminate; lateral roots +, endogenous, root apex multicellular, root cap +; tracheids with scalariform-bordered pits; leaves with apical/marginal growth, venation development basipetal, growth determinate; sporangia borne in pairs and grouped in terminal trusses, dehiscence longitudinal, a single slit; cells polyplastidic, microtubule organizing centres not associated with plastids, diffuse, perinuclear; male gametes multiflagellate, basal bodies staggered, blepharoplasts paired; chloroplast long single copy ca 30kb inversion [from psbM to ycf2].
Plant woody; lateral root origin from the pericycle; branching lateral, meristems axillary; cork cambium + [producing cork abaxially], vascular cambium bifacial [producing phloem abaxially and xylem adaxially].
EXTANT SEED PLANTS / SPERMATOPHYTA
Plant 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 [hence with p-hydroxyphenyl and guaiacyl lignin units, so no Maüle reaction]; root stele with xylem and phloem originating on alternate radii, not medullated [no pith], cork cambium deep seated; arbuscular mycorrhizae +; shoot apical meristem interface specific plasmodesmatal network; stem with vascular cylinder around central pith [eustele], phloem abaxial [ectophloic], endodermis 0, xylem endarch [development centrifugal]; 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; leaves with single trace from vascular sympodium [nodes 1:1]; stomatal pore with active opening in response to leaf hydration, control by abscisic acid, metabolic regulation of water use efficiency, etc.; leaves with petiole and lamina, development basipetal, blade simple; branches axillary (buds not associated with all leaves), exogenous; 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 linear, functional megaspore single, chalazal, lacking sporopollenin, megasporangium indehiscent; pollen grains landing on ovule; gametophytes dependent on sporophyte; male gametophyte development initially endosporic, tube developing from distal end of grain, gametes two, developing after pollination, with cell walls; 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, embryonic axis straight [shoot and root at opposite ends; plant allorhizic], white, cotyledons 2; plastid transmission maternal; ycf2 gene in inverted repeat, whole nuclear genome duplication [zeta duplication], 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.
ANGIOSPERMAE / MAGNOLIOPHYTA
Lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, 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 1:?; stomata brachyparacytic [ends of subsidiary cells level with ends of pore], outer stomatal ledges producing vestibule, reduction in stomatal conductance to increasing CO2 concentration; lamina formed from the primordial leaf apex, margins toothed, development of venation acropetal, overall growth ± diffuse, venation hierarchical-reticulate, secondary veins pinnate, 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 +, members each with a single trace, outer members not sharply differentiated from the others, not enclosing the floral bud; 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 columellate, endexine +, thin, compact, lamellate only in the apertural regions; nectary 0; carpels present, superior, free, several, ascidiate, with postgenital occlusion by secretion, stylulus short, hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, carinal, 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, functional megaspore, chalazal, lacking cuticle; female gametophyte four-celled [one module, nucleus of egg cell sister to one of the polar nuclei]; supra-stylar extra-gynoecial compitum +; ovule not increasing in size between pollination and fertilization; pollen grains landing on stigma, bicellular at dispersal, mature male gametophyte tricellular, germinating in less than 3 hours, pollination siphonogamous, tube elongated, growing between cells, growth rate (20-)80-20,000 µm/hour, apex of pectins, wall with callose, lumen 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, much larger than ovule at time of fertilization; endosperm diploid, cellular, heteropolar [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; dark reversal Pfr → Pr; Arabidopsis-type telomeres [(TTTAGGG)n]; 2C genome size 1-8.2 pg [1 pg = 109 base pairs], whole nuclear genome duplication [epsilon duplication]; protoplasm dessication tolerant [plant poikilohydric]; 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]]]]]: 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]]]]: vessel elements with scalariform perforation plates in primary xylem; essential oils in specialized cells [lamina and P ± pellucid-punctate]; tension wood +; 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 +; sesquiterpene synthase subfamily a [TPS-a] [?level], 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 position]; pollen tube growth intra-gynoecial; embryo sac bipolar, 8 nucleate, antipodal cells persisting; endosperm triploid.
[MONOCOTS [CERATOPHYLLALES + EUDICOTS]]: (extra-floral nectaries +); (veins in lamina often 7-17 mm/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; trichoblasts in atrichoblast [larger cell]/trichoblast cell pairs, the former further from apical meristem, in vertical files; endodermal cells with U-shaped thickenings; cork cambium in root [uncommon] superficial; stele oligo- to polyarch, < class="apo">medullated [with prominent pith], lateral roots arise opposite phloem poles; primary thickening meristem +; vascular bundles in stem scattered, (amphivasal), vascular cambium 0 [bundles closed]; tension wood 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; prophyll single, adaxial; leaf blade linear, main venation parallel, the veins joining successively from the outside at the apex, transverse veinlets +, unbranched [leaf blade characters: ?level], vein/veinlet endings not free, margins entire, Vorläuferspitze +, base broad, ensheathing the stem, sheath open, petiole 0, colleters + ["intravaginal squamules"]; inflorescence terminal, racemose; flowers 3-merous [6-radiate to the pollinator], polysymmetric, pentacyclic; P = T, each with three traces, median T of outer whorl abaxial, aestivation open, members of whorls alternating, [pseudomonocyclic, each T member forming a sector of any tube]; 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 , 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; embryo long, cylindrical, cotyledon 1, apparently terminal, with a closed sheath, unifacial [hyperphyllar], both assimilating and haustorial, plumule apparently lateral; primary root unbranched, not very well developed, stem-borne roots numerous, hypocotyl short, (collar rhizoids +); cotyledon with a closed sheath, unifacial [hyperphyllar], both assimilating and haustorial; no dark reversion Pfr → Pr; 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 supervolute-curved or variants, (margins with teeth, teeth spiny); 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 cells [?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 fluorescing blue under UV, green with NH3 [ferulic acid ester-linked]; (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; P = K + C, bicyclic [stamens adnate to/inside corolla/inner whorl only]; pollen starchy; embryo short, broad.
[POALES [COMMELINALES + ZINGIBERALES]]: primary cell wall mostly with glucurono-arabinoxylans; stomata subsidiary cells with parallel cell divisions; endosperm reserves starchy.
[COMMELINALES + ZINGIBERALES]: rhizodermal cells dimorphic; inflorescences with many-flowered cincinnal branches [helicoid cymes]; P = T; A opposite T; tapetum invasive or amoeboid. Back to Main Tree
Age. Divergence of the two clades dates to ca 114 m.y. (Janssen & Bremer 2004), while the figures in Wikström et al. (2001) are (85-)81, 73(-69) m.y., and in Bremer (2000b: largely fossil calibrations) ca 84 m.y.; Magallón and Castillo (2009) estimated ca 109.7 and 99.9 m.y. while Bell et al. (2010) offer the figures of (101-)88, 86 m.y.. However, Kress and Specht (2005) thought stem-group Zingiberales might be 158 m.y.o. (but ages of 124-122 m.y. in Kress & Specht 2006), while estimates are (114-)92(-83) m.y. in Merckx et al. (2008a), 85-83 m.y. in Mennes et al. (2013), and a mere 52.4 m.y. in Naumann et al. (2013).
Evolution. Divergence & Distribution. Monosymmetric flowers in this clade, especially in Zingiberales and Haemodoraceae, have a variety of very different morphologies; for different types of monosymmetry, see Rudall and Bateman (2004). Monosymmetric flowers can be optimised to this node, as by Endress (2011a), who suggested that it might be a key innovation here, interestingly, monosymmetry is associaed with the abaxial/ventral expression of the CYC gene (Bartlett & Specht 2011; Preston & Hileman 2012; Hileman 2014). It is also possible to optimise the change from a biseriate perianth (K + C) to a biseriate tepaloid perianth, with the stamens individually opposite each tepal, to this node (see above), which then has consequences for floral evolution in Zingiberales (c.f. Barrett et al. 2013). Enantiostyly is also common.
Chemistry, Morphology, etc. Tapetal variation in those few Zingiberales studied is extensive (Prakash et al. 2000; Furness & Rudall 2001; Simão et al. 2007).
Phylogeny. This clade 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) Commelinales were paraphyletic and included Zingiberales.
COMMELINALES Dumortier Main Tree.
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.
Age. Crown-group Commelinales are dated to ca 110 m.y.a. (Janssen & Bremer 2004: c.f. topology); the corresponding dates in Wikström et al. (2001) are (75-)71, 66(-62) m.y.a., while Bell et al. (2010) suggest an age of (91-)76, 70(-55) m.y.a.; estimates are (104-)75(-50) m.y. in Merckx et al. (2008a) and 84-47 m.y. in Mennes et al. (2013).
Note: Possible apomorphies 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 partly because many characters show considerable homoplasy, in addition, basic information for all too many is very incomplete, frequently 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 (see above).
Evolution. Genes & Genomes. There has been a reduction in the GC content of the genome in this clade (Smarda et al. 2014).
There is a five base pair insertion in the matK gene in members of Hanguanaceae and Pontederiaceae (Tamura et al. 2004a) and it was absent in Haemodoraceae, but no other taxa were sampled.
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). 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]]]]; 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) suggested 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; embryo small; cotyledon not photosynthetic.
HANGUANACEAE Airy Shaw Back to Commelinales
Mucilage canals +; hairs multicellular, branched; epicuticular waxes 0; leaves spiral, with petiole and blade; plant dioecious; inflorescence branched-spicate, flowers sessile; T small; staminate flowers: 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 none, 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?; 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]
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), and Bayer et al. (1998b), Tillich and Sill (1999), and Rudall et al. (1999), all general.
Previous Relationships. Hanguana was often included in Flagellariaceae (now in Poales), Cronquist (1981) included them in his broadly-circumscribed Liliales, 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, Vorläuferspitze 0 [?level]; andromonoecy common; inflorescences axillary (terminal), (boat-like bracts conspicuous); flowers open one day; K + C, C deliquescent; (G ), septal nectaries 0; micropyle (exo)/endostomal (nucellus apex exposed), outer integument 3-7(-10) cells across, inner 2, (parietal tissue none, 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 +, cotyledon ± lateral, suspensor 0; n = 4³; coleoptile +.
40<[list]/652. Tropical and temperate.[Photos - Collection.]
Age. Stem group Commelinaceae are dated to ca 89 m.y. (Janssen & Bremer 2004: c.f. topology).
1. 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; embryo undifferentiated; 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.
2. Commelinoideae Eaton
Rather succulent herbs, (annual); (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 blade vernation involute); (inflorescence axillary), (prophyll lateral); flowers with the median sepal adaxial, (obliquely monosymmetric [when monosymmetric, C often 2, adaxial members]), (enantiostylous); (T), 1- or 3- trace, blue, pink or white (yellow), (C tubular); A 1-6, (adnate to C), heteranthy common, 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.]
Age. Crown-group Commelinoideae are dated to ca 62 m.y. (Janssen & Bremer 2004).
Synonymy: Ephemeraceae Batsch, nom. rej., Tradescantiaceae Salisbury
Evolution. Pollination. For the evolution of breeding systems in Tradescantieae, see Hertweck and Pires (2004).
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 construction are 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 then being opposite each tepal member, 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 stamen hairs, if present, are not moniliform. Tradescantieae have stomata with 2-6 subsidiary cells, moniliform stamen 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 paraphyletic, Gibasis is polyphyletic (Hertweck & Pires 2004). Spalink et al. (2009) outlined relationships in Aneilema.
Classification. Wade et al. (2006) provide a subtribal classification of Tradescantieae; some subtribes are paraphyletic; generic limits in Tradescantieae will have to be adjusted (see Hertweck & Pires 2004).
[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
Proanthocyanins +; stem vascular tissue various; (stomata tetracytic); hairs often wooly; leaves two-ranked, ventralized isobifacial [oriented edge on to the stem] or 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 curved or coiled), (filament winged); tapetum glandular, cells 2-4-nucleate; pollen with raphides, (in tetrads); septal nectaries 0, (style impressed), stigma large; ovules many/carpel, outer integument 1-2 cells across, inner integument 2-3 cells across, (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 Fl. Austral. 25. 1987; Hamann 1998b).
Age. Crown group Philydraceae are dated to (37-)33(-29) m.y. by Wikström et al. (2001) and ca 47 m.y. by Janssen and Bremer (2004).
Evolution. Divergence & Distribution. 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), Hamann (1962b: endosperm, 1966: much detail, 1998: general) and Adams (1987: 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
(Plant cormose); fructans, chelidonic acid, flavones +; vessel elements in roots often with simple perforation plates, (vessels also in stem and leaf); leaves two-ranked, isobifacial [oriented edge on to the stem], (margins [minutely] spiny); cyme bifurcated (not); prophyll ± lateral; flowers (large), (monosymmetric), plane of symmetry transverse to oblique; T connate; 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.
Age. Divergence within the crown group Haemodoraceae began ca 81 m.y. (Janssen & Bremer 2004).
1. Haemodoroideae Arnott
(Plant bulbose), roots red; tannins 0; hairs with distinctive basal cells; flowers enantiostylous, tannin cells 0; T (densely hairy inside - Lophiola); 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, rather scattered, in Africa, only southern (map: from Heywood 1978 [Africa]; Australia's Virtual Herbarium i.2014; Maas & Maas-van der Kamer 1993; Fl. N. Am. 26: 2002). [Photo - Flower, Fruit, Flower]
Age. The start of divergence within Haemodoroideae has been put at the early Eocene ca 47.9 m.y.a. (Hopper et al. 2009).
Synonymy: Dilatridaceae M. Roemer, Wachendorfiaceae Herbert, Xiphidiaceae Dumortier
2. Conostylidoideae Lindley
SiO2 sand +; tannin-containing cells; (epidermal walls thickened), hairs branched; flowers ± pubescent outside (and inside), (monosymmetric); T (not connate), (valvate); (A adnate to T), (with ± petel-like dorsal appendage); pollen 2-8 porate; ovary at least partly inferior; ovules 1-many/carpel; (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 (map: from Fl. Austral. 45. 1987). [Photo - Flower]
Age. Divergence within Conostyloideae began in the Eocene ca 42 m.y.a. (Hopper et al. 2009).
Synonymy: Conostylidaceae Takhtajan
Evolution. Divergence & Distribution. The restriction of Conostylidoideae to S.W. Australia is remarkable; Hopper et al. (2006, 2009) 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 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. (2009).
PONTEDERIACEAE Kunth, nom. cons. Back to Commelinales
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), leaf blade broad, initially surrounding petiole of older leaf, (linear), petiolate or not, 2ndaries transverse, sheath open or closed, often long-ligulate [= "stipules" sheathing to minute], colleters +; inflorescence with two inflorescence bracts; flowers open for one day, tristyly, enantiostyly, monosymmetry all common; T (large), adaxial inner tepal with markings, deliquescent, (4, 3), mostly blue or yellow, ± connate, (tube to 11 cm long); A adnate to T, of different lengths, (1, 3, 4), (staminodes 2), (tapetum glandular), filaments hairy, (winged); pollen 2- or 3-sulcate; (septal nectaries 0); (1 carpel fertile), (placentation parietal), stigma small, dry; ovule (1/carpel), micropyle bistomal, parietal tissue none (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.]
Age. Divergence within the crown-group Pontederiaceae is estimated to have occurred ca 39 m.y. (Janssen & Bremer 2004).
Evolution. 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 at each 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 Simpson and Burton (2006) 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