EXTANT SEED PLANTS

Plant woody, evergreen; nicotinic acid metabolised to trigonelline; primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins rich in guaiacyl units; true roots present, xylem exarch, branching endogenous; arbuscular mycorrhizae +; shoot apical meristem complex; 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(-8) mm/mm²; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores] +, grains mono[ana]sulcate, exine and intine homogeneous, ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development endo/exosporic, 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, mitochondrial nad1 intron 2 and coxIIi3 intron present.

MAGNOLIOPHYTA

Plant woody, evergreen; lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, non-hydrolysable tannins, quercetin and/or kaempferol +, apigenin and/or luteolin scattered, cyanogenesis via tyrosine pathway [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 sieve plate, companion cells from same mother cell that gave rise to the tube, the sieve tube with P-proteins; nodes unilacunar; stomata with ends of guard cells level with aperture, paracytic; leaves with petiole and lamina [the latter formed from the primordial leaf apex], development of venation acropetal, 2ndary veins pinnate, fine venation reticulate, vein endings free; flowers perfect, polysymmetric, parts spiral [esp. the A], free, development in general centripetal, numbers unstable, P not differentiated, outer members not enclosing the rest of the bud, 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, pollen subspherical, binucleate at dispersal, trinucleate eventually, tectum continuous or microperforate, exine columellar, endexine thin, compact, lamellate only in the apertural regions, 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 , nectary 0, G free, several, ascidiate, with postgenital occlusion by secretion, few [?1] ovules/carpel, ovules marginal, anatropous, bitegmic, micropyle endostomal, integuments 2-3 cells thick, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte ?type, stylulus short, stigma ± decurrent, wet [secretory]; P deciduous in fruit; seed exotestal; double fertilisation +, endosperm ?diploid, cellular [first division oblique, micropylar end initially with a single large cell, chalazal end more actively dividing], copious, oily and/or proteinaceous, embryo cellular ab initio; germination hypogeal, seedlings/young plants sympodial; Arabidopsis-type telomeres [(TTTAGGG)_n]; whole genome duplication, single copy of LEAFY and RPB2 gene, knox genes extensively duplicated [A1-A4], AP1/FUL gene, paleo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and PHYA/PHYC gene pairs.

Possible apomorphies are in bold. Note that the actual level to which many of these features, particularly the more cryptic ones, should be assigned is unclear, because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied. Furthermore, details of relationships among gymnosperms will affect the level at which some of these characters are pegged.

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

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

POALES [COMMELINALES + ZINGIBERALES]: Primary cell wall mostly with glucurono-arabinoxylans; stomata paracytic or tetracytic, neighbouring cells with parallel cell divisions; endosperm starchy.   Back to Main Tree

The stem group for this clade dates to about 120 million years before present, while Poales diverged from [Commelinales + Zingiberales] ca 117 million years before present (from Janssen & Bremer 2004). Sap-eating chinch bugs of the Hemiptera-Lygaeidae-Blissinae have been recorded from taxa throughout this clade, although they occur on Poales and especially Poaceae most frequently (Slater 1976).

For primary cell wall composition, see literature in Harris (2005); Arecaceae sampled are somewhat intermediate between this clade and other monocots. For stomatal development, see Tomlinson (1974) and Rudall (2000); development in Dasypogonaceae is apparently unknown.

POALES Small  Main Tree, Synapomorphies.

Mycorrhizae absent; vessels also in stem and leaf; SiO₂ epidermal; raphides 0; P = K + C, micropyle bistomal, style well developed, stigmas small, stigma dry; endosperm nuclear, embryo size?; cotyledon hyperphyllar, haustorial [?level]; mitochondrial sdh3 gene lost. - 17 families, 997 genera, 18325 species.

Divergence within the Poales clade begins ca 113 million years before present (Janssen & Bremer 2004) or 109-106 million years before present (Leebens-Mack et al. 2005), while Wikström et al. (2001) suggest an age for the clade of 87-83 million years before present, divergence beginning 72-69 million years before present.

Rapateaceae are sister to other Poales in some analyses (e.g. Davis et al. 2004), albeit with little support. The general pattern of movement of genes from the mitochondrion to the nucleus is interesting; it suggests that Bromeliaceae and Typhaceae (of the taxa sampled) are sister to other Poales (Adams & Palmer 2003), and of course Bromeliaceae alone have septal nectaries, along with Rapateaceae, in Poales. Bromeliaceae, Sparganiaceae and Typhaceae are often basal branches with respect to other clades in Poales (Givnish et al. 2005, 2008 [but rooting]; also Graham et al. 2006). Interestingly, Graham et al. (2006) also found an accelerated rate of change in the chloroplast genes they sequenced in the Poales - but not in the representatives of these three families (other genes also show accelerated evolution, see G. Petersen et al. 2006b).

Within Poales there are some well-supported groups, the Xyridaceae, Juncaceae and Poaceae and their respective relatives, although the exact composition of the first clade remains somewhat unclear. There is support for these three groups forming a larger clade (Givnish et al. 2005; Chase et al. 2006), perhaps compatible with the distribution of deletions in the chloroplast inverted repeat ORF 2280 region and absence of a full accD gene (Hahn et al. 1995; Katayama & Ogihara 1996). Eriocaulaceae, Poaceae, Cyperaceae and Juncaceae at least have lateral roots originating opposite the phloem of the vascular tissue, in Restionaceae and Bromeliaceae they originate opposite the xylem. Note that at least some of the Poaceae and Cyperaceae groups have distinctive cellulose orientation in the outer epidermal walls of their roots, but that some Typhaceae and Bromeliaceae do not (Kerstens & Verbelen 2002); one wonders what improved sampling will show. The order itself does not have very strong support. The topology of the tree in early versions of this site was based on the work of K. Bremer (2002) in particular, and also that of Harborne et al. (2000), but Janssen and Bremer (2004) suggested a rather different set of relationships, albeit some had little support.

A three-nucleotide deletion in the atpA gene characterises Sparganiaceae + Typhaceae + Bromeliaceae (Davis et al. 2004), although there was little bootstrap support for this group (but see also Givnish et al. 2005, 2007; cf. Givnish et al. 2006b). Similarly, Typhaceae are placed sister to Bromeliaceae with weak jacknife support but strong Bayesian posterior probabilities in a study of Poales (Bremer 2002). Indeed, recent work suggests that Typhaceae and Bromeliaceae form a clade sister to other Poales, and Rapateaceae are in turn sister to the remainder (Chase et al. 2006; see also Rudall & Linder 2005; Givnish et al. 2005, 2007, but rooting; Graham et al. 2006 for this latter position). Within the remaining Poales there are two main clades.

1. Cyperaceae and Eriocaulaceae and their relatives may form one clade. Xyridales of Kubitzki (1998c) had included Mayacaceae, Xyridaceae, Eriocaulaceae and Rapateaceae. There was some evidence for a group with the first three families, perhaps, but not very probably, also including Rapateaceae (Rapateaceae are sister to [Juncaceae + Xyridaceae + Poaceae groups] in Givnish et al. 2005). Bremer (2002) noted that Mayacaceae and Hydatellaceae might be weakly associated with Xyridaceae or Eriocaulaceae, depending on what taxa were included in the analysis, but there were a number of long branches in this area and he excluded the first two families from his final analysis (Chase et al. 2006 also found the position of Hydatellaceae to be problematic; for the association of Mayacaceae with Eriocaulaceae and Xyridaceae, see also Campbell et al. 2001). Davis et al. (2004) found a more complex set of relationships, although with very little support. Members of this group of families are in adjacent branches along the spine of the tree, with one including Flagellariaceae, the Juncaceae group, some Xyridaceae, Mayacaceae, and perhaps Hydatellaceae. Note also that Xyridaceae and Mayacaceae have more or less clawed petals and anthers with an exothecium. Finally, some studies link Mayacaceae with Rapateaceae, and both have poricidal anthers. Clearly, there are a number of distinctive characters in this group of families, but relationships within the group remained unclear.

The situation seems, however, to be becoming tidier. Saarela et al. (2006, esp. 2007) have recently shown that Hydatellaceae themselves are in fact completely misplaced, and are members of Nymphaeales, a position that has very strong molecular and morphological support. The three members of the old Xyridales that remain here may form a grade at the base of this first clade: Mayacaceae are sister to the other members, then [Xyridaceae + Eriocaulaceae] are sister to Cyperaceae and their relatives (Givnish et al. 2006b; Chase et al. 2006: the topology of the tree in Graham et al. 2006, although with poor sampling, is consistent with such relationships).

2. Poaceae and their immediate relatives form the other clade. (Note that in versions 7 [before November] and earlier of this site, Eriocaulaceae and their relatives were weakly linked to Poaceae et al.). For a molecular study, see Bremer (2002), and for a useful detailed morphological and molecular analysis combined, see Michelangeli et al. (2003), also Hahn et al. (1995: details on deletions in the ORF 2280 region).

General information is taken from Linder and Rudall (1993) and (2005: detailed discussion of morphological evolution and diversification in Poales); see Doyle et al. (1991) for chloroplast inversions, Prychid et al. (2004) for SiO₂ bodies, Ong and Palmer (2006) for the rps14 nuclear gene/mitochondrial pseudogene system, and for seedling morphology and evolution, see Tillich (2007).

Includes Anarthriaceae, Bromeliaceae, Centrolepidaceae, Cyperaceae, Ecdeiocoleaceae, Eriocaulaceae, Flagellariaceae, Joinvilleaceae, Juncaceae, Mayacaceae, Poaceae, Rapateaceae, Restionaceae, Thurniaceae, Typhaceae, Xyridaceae.

Synonymy: Eriocaulineae Thorne & Reveal, Xyridineae Thorne & Reveal - Avenales Bromhead, Bromeliales Dumortier, Centrolepidales Takhtajan, Cyperales Hutchinson, Eriocaulales Nakai, Flagellariales (Meisner) Reveal & Doweld, Hydatellales Reveal & Doweld, Juncales Dumortier, Mayacales Nakai, Rapateales (Meisner) Reveal & Doweld, Restionales J. D. Hooker, Typhales Dumortier, Xyridales Lindley - Bromelianae Reveal, Hydatellanae Reveal, Juncanae Takhtajan, Poanae Reveal & Doweld, Rapateanae Doweld, Typhanae Reveal - Bromeliidae C. Y. Wu, Juncidae Doweld - Bromeliopsida Brongniart, Juncopsida Bartling

Typhaceae + Bromeliaceae: three-nucleotide deletion in the atpA gene.

TYPHACEAE Jussieu, nom. cons.   Back to Poales

Plant rhizomatous; flavonoids +; SiO₂ bodies 0; starch grains pteridophyte-type, amylophilic; leaves two-ranked; plant monoecious; inflorescences complex; flowers very small, P chaffy, A 1-8, tapetum plasmodial, 8 nuclei/cell, pollen trinucleate, monoulcerate, nectary 0, G pseudomonomerous, 1 pendulous apotropous ovule/carpel, style + [?], branches long, stigma rather elongated, on one side; endosperm helobial, cell wall formation in small chalazal chamber before that in large micropylar chamber, perisperm thin, embryo long, slender; x = 15; ORF 2280 deletion; seedling with hypocotyl and collar hairs.

2/ca 25. More or less world-wide.

Typhaceae are ca. 109 million years old, the two genera included separating ca 89 million years before present (Janssen & Bremer 2004).

Similar rusts are shared by the two genera (Savile 1979), and they are palynologically almost identical.

Much information is taken from Kubitzki (1998d: general); see also D. Müller-Doblies (1970: inflorescence and flower) and Grayum (1992: pollen).

Sparganium L.

Sheath not distinct; inflorescence as globose heads; P 1-6, when 3, median member adaxial; staminate flowers: anthers extrorse-latrorse; carpellate flowers: antipodal cells multiply after fertilisation, stigma papillate; fruit a spongy drupe, with micropylar plug, P persistent; testa membranaceous; perisperm with oil; phanomer [unifacial, ± assimilating], hypophyll quite well developed.

1/14. Temperate and Arctic, little in S. hemisphere, but to New Zealand (Map: see Hultén 1958, 1962; Meusel et al 1965; Hultén & Fries 1986).

• Sparganium is a rhizomatous aquatic with linear leaves and inflorescences with a few spherical heads of flowers, carpellate towards the base of the inflorescence and staminate towards the apex.

Some flowers of Sparganium may have a second, empty loculus, or there may even be three fertile loculi (Dahlgren et al. 1985). On the other hand, fossil Sparganium may have up to 7-locular fruits (Cook & Nicholls 1986)!

See Cook and Nicholls (1986, 1987) for a monograph, and U. Müller-Doblies (1970) for flower and embryology.

Typha L.

Cuticular waxes as aggregated rodlets; sheath distinct; inflorescence densely spicate; P 0, staminate flowers: A connate, tapetal cells ?8-nucleate; carpellate flowers: long hairs on pedicels; fruit an achene with a little operculum; endosperm also with oil.

1/8-13. Temperate and tropical regions worldwide (Map: see Hultén 1962; Meusel et al. 1965; Hultén & Fries 1986; Flora Base 2005 - somewhat notional - note that the map in Knobloch & Mai 1986 differs very considerably from its source, Meusel et al. 1965). [Photos - Collection]

• Typha is a robust, rhizomatous herb that likes damp conditions and has erect, linear leaves and distinctive, elongated, densely cylindrical inflorescences, the part containing the carpellate flowers being borne below and separate from the part with the staminate flowers.

For general information, see Thieret and Luken (1996: S.E. U.S.A.).

Synonymy: Sparganiaceae nom. cons. Hanin

BROMELIACEAE Jussieu, nom. cons.   Back to Poales

Rosette plants, usu. herbs; (C-glycosylated/6-oxygenated) flavones, flavonols +; vessel elements with scalariform perforations; mucilage +; cuticular waxes as aggregated rodlets; stomata with oblique cell divisions; water storage tissue in mesophyll, fibrous bundle sheaths +; indumentum lepidote; leaves spiral, curved, thick, horny, base dilated, no distinct sheath; inflorescence bracts often colored; (C often with basal scales and/or longitudinal callosities; A basally connate; adnate to C), septal nectaries +, 2-many ovules/carpel, one cell layer of nucellus at micropyle, epidermal cells elongated, micropyle ?, style + long, apically ± trifid, conduplicate-spiral, stigmas also wet; fruit a septicidal capsule, K persistent; seeds testal-tegmic; endosperm helobial, cell wall formation in small chalazal chamber precedes that in large micropylar chamber, embryo (long), cylindrical, often lateral; hypocotyl and hypophyll common; x = 25, chromosomes 2.75³ µm long.

57[list]/1400 - eight groups below. (Sub)tropical America; W. tropical Africa (map: from Givnish 2004a). [Photos - Flower.]

1. Brocchinioideae Givnish

(Tank bromeliads, stem erect and with intracauline adventitious roots); leaves with stellate chlorenchyma, margin ?; C minute, G ± inferior, septal nectary above the ovules; seeds caudate (basal tuft of hairs +); n = ?9, 23.

1/21. South America, the Guyana Highlands.

For the association of Ayensua with Brocchinia, see also Horres et al. (2000).

Rest: cap cells of trichomes dead; septal nectaries below the ovules.

2. Lindmanioideae Givnish

Stellate chlorenchyma 0; leaf margin entire/serrate; K contorted, stigmas straight; seeds caudate; cotyledonary hypophyll blade-like.

1-2/43. South America, the Guyana Highlands.

3. Tillandsioideae Burnett

Epiphytes, air bromeliads (also tank forming), roots often for attachment only (0); scales radially symmetrical; leaf margin entire; (flowers in inflorescence two-ranked); ovules with chalazal appendage, (outer integument ca 5 cells across); seeds caudate because of greatly elongating outer integument, apical and/or basal tufts of hair usu. derived from longitudinal splitting of the outer integument; (n = 17, 21), karyotype bimodal; primary root none or soon aborting.

9/1015: Tillandsia (540: polyphyletic), Vriesia (195: poly/paraphyletic), Guzmania (170), Werauhia (70), Racinaea (60). Almost the range of the family in America.[Photo - Flower]

The hairs in Tillandsioideae develop in a variety of ways (Palací et al. 2004; Barfuss et al. 2005) and variation in stigma morphology is also great (Brown & Gilmartin 1989).

For phylogenetic relationships, see Barfuss et al. (2004, 2005, the latter with a tribal classification and extensive discussion on morphology); generic limits need attention!

Synonymy: Tillandsiaceae Wilbread

4. Hechtioideae Givnish

Xeromorphic [hypodermal sclerenchyma +, internal water storage tissue, chlorenchyma undifferentiated; trichomes in parallel rows]; leaf margin serrate (entire); plant dioecious; (G subinferior), stigma simple-erect; seeds winged (not); cotyledonary hypophyll blade-like.

1/51. Texas, Mexico, N. Central America.

5. Navioideae Harms

Xeromorphic; water storage tissue peripheral; stellate chlorenchyma 0; leaf margin serrate/entire; C minute; seeds winged or not.

5/105: Navia (98). Guyana Highlands, N.E. Brasil.

6. Pitcairnioideae Harms

Scales ± divided; leaf margin?; (flowers monosymmetric), G to inferior, ovules with chalazal appendage, (outer integument ca 5 cells across; several cells layers of nucellus at micropyle); seeds tailed, body cells differing from tails, winged, or not; embryo lateral or not; (karyotype bimodal); hypocotyl quite long, cotyledonary hypophyll blade-like, (collar rhizoids - Pitcairnia).

6/515: Pitcairnia (280), Dyckia (125), Pepinia (68). Mexico to Chile, Pitcairnia feliciana W. Africa.

7. Puyoideae Givnish

Rather xeromorphic [hypodermal sclerenchyma +, internal water storage tissue, chlorenchyma undifferentiated; trichomes in parallel rows, foliar trichomes with well developed wings]; leaf margin serrate; flowers monosymmetric, K contorted, C clawed, tightly spiralled after anthesis, several cells layers of nucellus at micropyle [?all]; seeds circumferentially winged; cotyledonary hypophyll blade-like.

1/195. Mountains, etc., Costa Rica and Guyana to Chile and Argentina. [Photos - Puya Flower, Puya Habit, Puya Habit.]

For a morphological study of Puya subgenus Puya, see Hornung-Leoni and Sosa (2008).

8. Bromelioideae Burnett

Epiphytes, often tank bromeliads, roots often for attachment only; scales irregular peltate; leaf margin entire/serrate; (perianth tube/hypanthium +), G inferior, ovules with chalazal [= funicular] appendage, (micropyle bistomal), stigma conduplicate spiral; fruit baccate, seed usu. without an appendage; sarcotesta [gelatinous] common; embryo lateral; (n = 17, 21); (cotyledon not photosynthetic), collar rhizoids +, primary root prominent, short hypocotyl present.

31/722: Aechmea (185), Neoregelia (100), Billbergia (65), Bromelia (50), Hohenbergia (50), Nidularium (50). Mexico and the West Indies to Chile. [Photo - Flower, Fruit, Flower, Flower.]

Generic limits and general phylogenetic relationships in Bromelioideae are unclear (Horres et al. 2007).

• Bromeliaceae are often rosette plants, the leaves always being tough, spirally arranged, lacking a distinct sheath, and often with spiny-toothed margins; the indumentum is scaly (lepidote); and the terminal inflorescence is prominently bracteate, the bracts sometimes being coloured. The flowers have a calyx and corolla, and the petals, although free, are erect and form a tube.

Stem-group Bromeliaceae are dated to ca 112 million years before present, divergence within the crown group to ca 96 million years before present (Janssen & Bremer 2004: Brocchinia not included). However, Givnish et al. (2004a, 2008) suggest comparable ages of 84 and 23 million years before present respectively, with radiation from an ancestral home on the Guayana Shield (see also Givnish et al. 1997), while Wikström et al. (2001) suggests a stem group age of 72-69 million years before present... Pitcairnia feliciana seems to have moved to Africa by long distance dispersal (Givnish et al. 2008). Some two thirds of Bromeliaceae have CAM metabolism, although details of the evolution of this feature remain unclear (Crayn et al. 2000, 2004; Reinert et al. 2003; Schulte et al. 2005); it has evolved more than once in the family. Givnish et al. (2004a, 2008) provide a phylogeny and discuss the biogeography of the group, while Givnish et al. (2008) also discuss the evolution of CAM, bird pollination, epiphytism and xeromorphic traits (see also Smith et al. 2005). Riodininae-Riodininae larvae may be found on Bromeliaceae (and Orchidaceae: Hall 2003 and references).

The diversity of growth forms in Bromeliaceae is well known. Many taxa are terrestrial, and have a well-developed root system. Epiphytism is common, and here the roots may be for attachment only. Tillandsioideae have rather elegant peltate trichomes that take in water, taxa like Tillandsia usneoides (Spanish moss) lacking roots, the plants growing happily on any available support, including telegraph wires (hairs in Tillandsia may also reflect light and so provide photoprotection: Pierce 2008). A few Tillandsioideae also have tanks, but these are especially well developed in Bromelioideae. In this latter subfamily, roots may grow into the tank where they absorb the contents; Pittendrigh (1948) noted that such roots were mycorrhizal, while roots growing into the soil were not obviously mycorrhizal. A diverse fauna showing considerable endemism is associated with these tanks, including many insects, even specialised diving beetles (Dystiscidae) whose evolution may be almost contemporaneous with the appearance of the tank habitat (Balke et al. 2008), land crabs, earthworms, ostracod crustaceans, protists and the like (Thienemann 1934; Kitching 2000, general; Greeney 2001, bibliography). In Trinidad, at least, mosquitoes that breed in the tanks help spread malaria (Pittendrigh 1948). Brocchinia is only small genus, but it has a great variety of ways in which nitrogen is taken up, different growth forms, etc. For possible carnivory in Brocchinia reducta, see Givnish et al. (1984).

The flowers of Tillandsia are shown as being inverted, but those of Bilbergia have the normal position with an abaxial median sepal (Spichiger et al. 2004); however, the former position is incorrect (W. Till, pers. comm.). Tapetum development is described as being intermediate, the cells being initially secretory, but tending to invade later (Sajo et al. 2005). The superior ovary of Bromeliaceae such as Tillandsioideae may be secondarily so (Böhme 1988; Sajo et al. 2004b), although I find it difficult to understand why the vascular traces to the various floral organs should then often depart independently in taxa with these "superior" ovaries (they are fused when the ovary is inferior). Variation in ovule morphology is extreme (e.g. Gross 1988a).

For relationships, etc., I follow those in Givnish et al. (2007; 1 gene, good generic sampling, few species, but note rooting of their Fig. 1), which are rather similar to those of Schulte et al. (2005: focus on Bromelioideae). In earlier studies, Bromelioideae were monophyletic, even when Pitcairnioideae were included (Crayn et al. 2004), however, in some studies (Horres et al. 2000) Puya did not link with them. Hechtia (P: 55 - circumferential winging, as with Navia), were of uncertain position, not linking with either major group (Tillandsioideae, Bromelioideae + Pitcairnioideae) in Horres et al. (2000), but were weakly linked with Tillandsioideae in Crayn et al (2004); in that study Navia was polyphyletic. Support for Pitcairnioideae is weak (55% - Terry et al. 1997). The subfamily is not apparent in Horres et al. (2000), although there is a group of Pitcairnioideae genera evident, albeit with <50% bootstrap. See also Crayn et al. (2004) for phylogenetic problems with Pitcairnioideae; it has of course turned out to be eminently paraphyletic (see Givnish et al. 2007).

For relationships, see Terry et al. (1997 - ndhF), Crayn et al. (2000, 2004 - matK + rps16), Horres et al. (2000 - trnL) and Givnish et al. (2004b: ndhF). For information on stigma morphology, see Brown and Gilmartin (1988, 1989), for nectaries, Böhme (1988) and Sajo et al. (2004b), for seed anatomy, Gross (1988a) and Varadarajan and Gilmartin (1988a), for the ovule, Sajo et al. (2004a), for germination, Gross (1988b), for chromsomal evolution, see Gitaí et al. (2005), for phytoliths, see Piperno (2006), for cultivated bromeliads, Rauh (1990), etc., for rhizome and root anatomy, see Proença and Sajo (2008), and for general information, Varadarajan and Gilmartin (1988b), Smith and Till (1998) and Benzing (2000). See also the World Checklist of Monocots

Rapateaceae [Thurniaceae [Juncaceae + Cyperaceae]] [[Anarthriaceae [Restionaceae + Centrolepidaceae]] [Flagellariaceae [Joinvilleaceae [Ecdeiocoleaceae + Poaceae]]]]: little oxalate accumulation; embryo minute, ± undifferentiated.

The exact condition of the embryo of the ancestor of this group is unclear. Malcomber et al. (2006) described the embryo of Joinvilleaceae and Ecdeicoleaceae as being undifferentiated, embryos of Centrolepidaceae seem to be undifferentiated (Hamann 1975), those of Restionaceae, largely undifferentiated (Linder et al. 1998), Mayacaceae, undifferentiated (Stevenson 1998), Eriocaulaceae, "poorly differentiated", or with "no exomorphological differentiation" (Stützel 1998). Embryos of the Cyperaceae group are described as being small, but they are more or less differentiated. Whatever its state of differentiation, the embryo is rather broad.

For oxalate accumulation, see Zindler-Frank (1976); I do not know about accumulation in Xyridaceae and Eriocaulaceae (the latter has calcium oxalate crystals, at least) and the small families in the Anarthriaceae-Poacaeae clade.

RAPATEACEAE Dumortier, nom. cons.   Back to Poales

Plants rhizomatous, Al accumulators; some vascular bundles amphivasal; vessels in leaf?; mucilage cells +; cuticular wax with wax globules or wax 0, stomatal guard cells dumbbell-shaped; leaves (spirally) two-ranked, (petiole + lamina), sheath distinct, open or asymmetrical and conduplicate, uniseriate [slime-secreting] colleters +; inflorescence scapose, axis usu. indeterminate, units cymose, capitate (head subtended by spathaceous bracts), flowers with several basal "bracteoles", large; C basally connate, A basally connate, adnate to C or not, porose, anther wall of the Reduced type, microsporogenesis simultaneous [tetrads tetrahedral], 1-many (basal) apotropous ovules/carpel, micropyle bistomal, (several antipodal calls), nucellar epidermal cells often radially elongated, outer integument 3-10 cells across, funicular obturator +, style +, stigma capitate; fruit a septicidal capsule; exo- (and endo)testa with SiO₂, endotestal cells with U-shaped thickenings, cuticular layer between testa and tegmen, tegmen tanniniferous; hypophyll with median sheath lobe, no collar or rhizoids, primary root at most short; n = 11 [Maschalocephalus]; 26; seedling?

16[list]/94. Tropical South America, West Africa (one species): three subfamilies below. (Map: from Givnish 2004a.) [Photo - Epidryos Habit © A. Gentry, Stegolepis Flower © G. Davidse.]

1. Rapateoideae Maguire

Involucral bracts long; 1 ovule/carpel; seeds ovoid-oblongoid, (with papillate apical appendage).

3/29. The Guianas to Bolivia and the Matto Grosso.

2. Monotremoideae Givnish & P. E. Berry

1 ovule/carpel; seeds ovoid-oblongoid, white-granulate [muriculate], with flattened apical appendage.

4/8. Guiana, upper Rio Negro in Colombia and Venezuela, Maschalocephalus dinklagei in Sierra Leone and Liberia.

3. Saxofridericioideae Maguire

(Leaves petiolate - Saxofridericieae; sheath with auricles - Stegolepis); seeds prismatic, pyramidal, lenticular or crescent-shaped.

9/54: Stegolepis (30+). N. South America, esp. the Guyana Highlands, Panama.

• Rapateaceae are rosette herbs with capitate, scapose inflorescences bearing rather conspicuous flowers; the perianth is differentiated into calyx and corolla, there are six stamens, and the anthers dehisce by pores.

Stem-group Rapateaceae are dated to ca 112 million years before present, divergence within the crown group to ca 79 million years before present (Janssen & Bremer 2004). Maschalocephalus dinklagei, the only African representative of the family, may have arrived there by long distance dispersal (Givnish et al. 2004a).

Septal nectaries seem not to occur in Rapateaceae except Monotremeae, but there are also reports of humming bird pollination of genera other than Monotremeae (Stevenson et al. 1998a); Vogel (1981) was not sure if nectaries were to be found in the family, and Tiemann (1985) does not mention them. The ovules are described as being crassinucellate (e.g. Rudall 1997), but in some illustrations (Tiemann 1985) they appear to be tenuinucellate.

Some information is taken from Stevenson et al. (1998a); for anatomy, see Carlquist (1969); for ovules and seeds, see Venturelli and Bouman (1988). Givnish et al. (2004a) provide a phylogeny, subfamilial classification and discuss the biogeography of the group, and the World Checklist of Monocots should also be consulted.

[[Eriocaulaceae + Xyridaceae] [Mayacaceae [Thurniaceae [Juncaceae + Cyperaceae]]]] [[Anarthriaceae [Restionaceae + Centrolepidaceae]] [Flagellariaceae [Joinvilleaceae [Ecdeiocoleaceae + Poaceae]]]]: (isoflavonoids +); pollen trinucleate, septal nectary 0, ovules tenuinucellate;.

[Eriocaulaceae + Xyridaceae] [Mayacaceae [Thurniaceae [Juncaceae + Cyperaceae]]]: flavonoids +; leaves spiral; A basifixed; K persistent in fruit; deletions in ORF 2280 region, full chloroplast accD and mitochondrial sdh4 genes lost.

Judd et al. (2002) note that the four families of Poales they mention - scattered through this part of the tree - have nuclear endosperm. The distribution of the sdh4 gene deletion (see Adams et al. 2002b) is consistent with the topology of the tree presented by Bremer (2002); for the accD gene and ORF 2280 region, etc., see esp. Hahn et al. (1995) and Katayama and Ogihara (1996). Finally, branch lengths of the ndhF and other genes are notably longer in this part of the monocot tree than anywhere else (e.g. Givnish et al. 2005, 2006b; Saarela et al. 2006).

Eriocaulaceae + Xyridaceae: rosette plants; vessel elements with simple perforation plates; SiO₂ bodies 0; leaves spiral, also two-ranked; inflorescence terminal (axillary), scapose, with involucral bracts; (flowers monosymmetric, 2-merous); C clawed, A adnate to and opposite C, exothecium +, pollen more or less spiny, (ovary with carinal [?nectariferous] appendages); seed operculum ["embryostega"] +, tegmic in origin, cuticular layer between testa and tegmen.

Eriocaulaceae and Xyridaceae may have diverged ca 105 million years before present, the crown group of the former beginning to diversify ca 58 million years before present and that of the latter ca 87 million years before present (Janssen & Bremer 2004).

Note that Eriocaulaceae have a scape that is bractless (i.e., it is a "true" scape), while that of Xyridaceae may have bracts half way up.

ERIOCAULACEAE Martynov, nom. cons.   Back to Poales

(Vessel elements with scalariform perforations); stem with endodermis; calcium oxalate crystals +; leaf bundle sheath cells large, without chloroplasts; hairs common, various, on vegetative parts with foot cell and bulbous persistent usually dark colored basal cell; cuticle waxes as aggregated rodlets; leaf sheath not distinct; plants mon(di)oecious; receptacle ± flat, scape spirally twisted, with closed basal sheath; flowers small, median K adaxial, K open (connate), C scarious, staminate flowers: (A dorsifixed), tapetum cells uni(bi)nucleate, (microsporogenesis simultaneous), pollen spiraperturate; carpellate flowers: staminodes common, 1 pendulous straight [atropous] ovule/carpel, micropyle endostomal, antipodal cyst [formed by fusion of antipodal cells] +; P persistent; seeds endotestal, the anticlinal walls prominent, endotegmen tanniniferous; radicle 0; n = 9, 15, 20, 25; (ORF 2280 present).

10[list]/1160. Pantropical (to temperate), but esp. Guyana Highlands and S.E. Brasil (Map: from Hamann 1961; Giulietti & Hensold 1990; Fl. N. Am. 22: 2000; FloraBase 2004). 2 groups below.

1. Eriocauloideae

Plants usu. of aquatic habitats; roots and leaves with aerenchyma; C free, with black tips, glandular; staminate flowers: A 4-6, adnate to C.

1(-2?)/420: Eriocaulon (400). Pantropical (to Temperate).

2. Paepalanthoideae

Plants usu. terrestrial; (aerenchyma +); C often connate, (0); staminate flowers: (A bisporangiate/monothecal by fusion; antesepalous staminodes +), nectariferous pistillode +; carpellate flowers: carinal stylar appendages +, stigmas not vascularized, commissural.

9/760: Paepalanthus (485), Syngonanthus (200). New World, but esp. tropical South America.

Generic limits are in part unclear.

• Eriocaulaceae are nearly always rosette plants readily recognised by their “pipe-brush” inflorescences. These have slender peduncles that are more or less spirally twisted and ridged or angled, and many small flowers with rather scarious and inconspicuous corollas that are aggregated into dense heads. The base of the inflorescence is surrounded by a single closed leaf sheath.

Support for the monophyly of Eriocauloideae and Paepalanthoideae sampled was good (Unwin 2004: three genes).

In an anatomical survey of Brazilian Eriocaulaceae, secondary thickening was reported from species of Paepalanthus and Syngonanthus (Scatena et al. 2005). In Tonina the scape is not twisted, although it is also short; at the base is a sheathing adaxial prophyll that is shortly connate abaxially. In general, the flowers of Eriocaulaceae are tiny, yet they show a great deal of variation (e.g. Giulietti & Hensold 1990). The basal part of the corolla may become secondarily free; the dark-colored glands on the petals of Eriocaulon may be nectar-producing. Whether or not the nectariferous appendages actually produce nectar seems uncertain (Ramos et al. 2005), although Rosa and Scatena (2003) suggest that in at least some Paepalanthoideae the pistillode (in staminate flowers) and carinal nectariferous appendages (carpellate flowers) are nectariferous. When the style is commissural, it is unvascularised; the nectariferous appendage of Syngonanthus is in the position of the style of Eriocaulon, and both are vascularised (Coan & Scatena 2004). There has been major movement of ribosomal protein and succinate dehydrogenase genes from the mitochondrion in Lachnocaulon, at least (Adams & Palmer 2003).

Much general information is taken from Unwin (2004), also from Stützel (1998), that on inflorescence and flower from Stützel (1987), embryology and seed development are summarized in Scatena and Bouman (2001) and Coan and Scatena (2004), and floral anatomy is described by Rosa and Scatena (2003). See also the World Checklist of Monocots.

XYRIDACEAE C. Agardh, nom. cons.   Back to Poales

(Plant caulescent; monopodial); anthraquinones +; vascular bundles amphivasal; cuticle with insoluble [organic solvent] secretion; leaf sheath distinct; (flower monosymmetric), K (2 carinate), the median [abaxial] membranous, deciduous, or all persistent, C more or less clawed, ephemeral, connate or not, A extrorse or latrorse, (free; sporangia connate), anther wall of the Reduced type, exothecium +, endothecial thickenings spiral, many ovules/carpel, micropyle?, stigma often complex and lobed/infundibular; seed coat testal and tegmic, tegmen mechanical, (operculum chalazal); deletions in ORF 2280 region [?whole family].

5[list]/260. Pantropical to warm temperate. 2 groups below.

1. Xyridoideae

Leaves distichous, equitant, isobifacial, ligulate; (A 6), tapetal cells binucleate [Xyris], pollen elongate, not spiny, (bisulcate), staminodia 3, branched and with moniliform hairs on branch ends, ovules straight [atropous], placentation (intrusive) parietal; n = ?8, 9, 13, 14, 16, etc., extensive polyploidy; n = 9, 13, 17; ; cotyledonary hypophyll bifacial and photosynthetic, hypocotyl and collar rhizoids +.

1/225-300. Pantropical to warm temperate, 150 spp. in Brasil (Map: from Hamann 1960; FloraBase 2004). [Photo - Xyris Flower, Infructescence © H. Wilson.]

Mucilage is secreted by hairs in the leaf axils of Xyris (cf. Mayacaceae?).

2. Abolbodoideae

Leaves spiral (distichous, whether or not equitant, isobifacial - Achlyphila); (inflorescence branched; open - Achlyphila; with 1 or more pairs of opposite bracts along the scape - Achlyphila, Abolboda); (K 2 - Abolboda), (A introrse), staminodes usu. 0 (filiform - Abolboda), pollen spherical, inaperturate, ovules anatropous (slightly campylotropous; crassinucellate), micropyle bistomal [Aratitiyopea], ovary with vascularised carinal appendages [non-commissural] (0 - Achlyphila), style often solid; (exotesta mechanical - Orectanthe); n = 8-10, 13, 17.

4/26: Abolboda (22). South America, Guyana Highlands in particular (Map: from Campbell 2004).

Synonymy: Abolbodaceae Nakai (stomata also tetracytic; K 2-3, C [3], staminodia filform, tapetum plasmodial, ovules crassinucellate; endotestal cells large, alternating with projecting exotegmic cells, endosperm helobial.)

• Xyridaceae are rosette plants that sometimes have equitant leaves; they can be recognised best by their inflorescences and flowers. The inflorescences normally bear one or more pairs of bracts along the infloescence stalk. The flowers are borne in heads and have a conspicuous but ephemeral corolla.

The scape of Xyris is sometimes spirally twisted (cf. Eriocaulaceae!). Pollen is up to 185 µm in diameter in Orectanthe, these are about the largest grains in flowering plants. Placentation is very variable in Xyris, but that of the whole family may be basically parietal. Collar rhizoids are not drawn in Tillich (1994).

There are suggestions that Xyridaceae may not be monophyletic (Michelangeli et al. 2003; Davis et al. 2004, support very weak), but sampling needs to be improved. For the above subfamilial classification of the family as a result of detailed phylogenetic analysis of morphological variation, see Campbell (2004: q.v. for more information).

Additional information is taken from Carlquist (1960: general, inc. seed anatomy [operculum]), Tomlinson (1969: vegetative anatomy), Tiemann (1985), Stützel (1990), Kral (1972, 1998), Rudall and Sajo (1999: flower and seed), Sajo and Rudall (1999: leaf anatomy), Scatena and Bouman (2001: seed operculum), Judd et al. (2002: general), Benko-Iseppson and Wanderley (2002: cytology), Campbell (2004: much information) and Campbell and Stevenson (2008: floral morphology, esp. Aratitiyopea); see also the World Checklist of Monocots.

[Mayacaceae [Thurniaceae [Juncaceae + Cyperaceae]]]: air canals [?= septate aerenchyma].

MAYACACEAE Kunth   Back to Poales

Monopodial marsh plants; vessels also in leaf; stem with endodermis; SiO₂ bodies 0; stomata with oblique cell divisions; leaves flat, apically bidentate, univeined, without a distinct sheath, uniseriate colleters +; flowers axillary, prophyll broad; C ± clawed, A 3, opposite sepals, porose, anther wall of the Reduced type, with exothecium, tapetal cells uninucleate, placentation parietal, 6-30 straight [atropous] ovules/carpel, stigmatic lobes small; seed operculum ["embryostega"] +, tegmic in origin, cuticular layer between testa and tegmen, exotestal cells with U-shaped lignifications; primary root and cotyledonary hypophyllar sheath 0; n = 8.

1[list]/4-10. Mostly tropical and American (inc. S.E. U.S.A.), 1 sp. from Africa (Map: from Hamann 1961; Boutique 1971; Fl. N. Am. 22: 2000).

• Mayacaceae are small herbs of marshes looking rather like a club-moss. They have numerous spirally-arranged, apically-toothed leaves borne scattered along the stem and pink to white apparently axillary flowers with a clearly differentiated calyx and corolla.

Mayacaceae are vegetatively rather different from many other Poales. Anthers in some species are monothecal, the nucellar epidermis is thick basally and the outer layer of endosperm has protein. The inflorescence is sometimes described as being terminal, but the flowers examined seemed to be axillary and associated with a broad, adaxial prophyll-like structure. However, given the association of Mayacaceae with families that have scapose inflorescence with involucral bracts, the inflorescence of Mayacaceae bears re-examination.

Some information is taken from Tomlinson (1974: stomata), Thieret (1975: general), Venturelli and Bouman (1986: ovule and seed), and Stevenson (1998: general), but the family is poorly known. See also the World Checklist of Monocots.

Thurniaceae [Juncaceae + Cyperaceae]: 3-desoxyanthocyanins [1 + 2], luteolin 5-methyl ether +; trichoblasts from distal cell of pair; starch grains pteridophyte-type, amylophilic; stem angled, leaves 3-ranked, sheaths closed; inflorescence racemose; flowers small, T scarious, undifferentiated, microsporogenesis simultaneous [tetrads tetrahedral], pollen in tetrads, porate, ovules anatropous, crassinucellate, (outer integument ³3 cells across), style short, branches long; seeds testal-tegmic; chromosomes with diffuse centromeres; seedling collar inconspicuous, with rhizoids.

Divergence of this clade can be dated to ca 103 million years before present (Janssen & Bremer 2004).

Both Thurniaceae and Juncaceae have basically racemose (polytelic) inflorescences (Köbele & Tillich 2001); for possible variation in Cyperaceae, see that family. A three nucleotide deletion in the atpA gene also characterises this group (Davis et al. 2004).

THURNIACEAE Engler, nom. cons.   Back to Poales

Root stock upright, or trunk-forming; flavone C-glycosides +; vessel elements with scalariform perforations; stem bundles amphivasal [Prionium], SiO₂ also in parenchyma (0 - Prionium); cuticular waxes as aggregated rodlets; leaf margin serrate, (vascular bundles in pairs, abaxial inverted - Thurnia); stem angled; inflorescence capitate and involucrate or a much-branched panicle; perianth tube short, tapetal cells?, 1-few ascending ovules/carpel, [micropyle zig-zag], styles separate, or style with long branches; seeds arillate, testa of sclerenchymatous fibers and unthickened cells, tegmen tanniniferous [Thurnia]; phanomer [photosynthetic unifacial cotyledonary hyperphyll], hypocotyl + n =?.

2[list]/4. South Africa and Guyana region, Amazonia (Map: see Munro et al. 2001). [Photo - Thurnia Habit, Inflorescence, Prionium - Inflorescence.]

• Thurniaceae can be recognised by their erect stems, serrate leaves, and pentacyclic flowers with scarious perianth.

Stem-group Thurniaceae are dated to ca 98 million years before present, the crown group diverged ca 33 million years before present (Janssen & Bremer 2004).

The family is poorly known. Is pollen development simultaneous? Tillich (1994) describes the seedling as being similar to that of Juncaceae.

Thurniaceae are sister to Juncaceae + Cyperaceae, with strong support (Givnish et al. 1999; Bremer 2002; Davis et al. 2004), although Oxychloe was not included.

See Tiemann (1985) for micropyle type, and Williams and Harborne (1975) for chemistry. Other information is taken from Kubitzki (1998d: general) and Givnish et al. (1999); see also the World Checklist of Monocots.

Synonymy: Prioniaceae S. L. Munro & H. P. Linder

Juncaceae + Cyperaceae: luteolin +; micropyle endostomal; chloroplast rpl23 gene absent.

This is a notably speciose clade (Magallón & Sanderson 2001). It diverged from Thurniaceae ca 98 million years before present, itself splitting ca 88 million years before present (Janssen & Bremer 2004); a less likely age for the clade is 39-28 million years before present (Wikström et al. 2001). Bugs of the Hemiptera-Lygaeidae-Cyminae and -Pachygronthini are concentrated in this clade (Slater 1976). Clavicipitaceous endophytes have been recorded from some genera, but they are not as common as they are on Poaceae (Clay 1986, 1990); cf. also the distribution of the parasitic Claviceps itself.

The distributions of parasitic fungi suggest that Cyperaceae and Juncaceae are close (Savile 1979b). For fungal records on the two families, see Tang et al. (2007). Roalson et al. (2008) discuss chromosome evolution in the clade.

Muasya et al. (1998) suggested that Oxychloe (Juncaceae) was sister to Cyperaceae, with moderate support, other Juncaceae are paraphyletic, but with with poor support, while Prionium was sister to the whole clade, with good support (see also Muasya et al. 2000: sampling in Juncaceae poor). A study by Plunkett et al. (1995) even placed Oxychloe within Cyperaceae. The relationships of the latter genus in particular remained unclear (Drábková et al. 2003), although a position in Juncaceae, near Distichia, also a cushion plant, seems likely (Simpson 1995: morphological data; Roalson 2005; see especially Drábková & Vl&ctilde;ek 2007); part of the problem seems to have been caused by the identity of the material from which early molecular samples of the genus were obtained (Kristiansen et al. 2005).

JUNCACEAE Jussieu, nom. cons.   Back to Poales

Plant glabrous (not Luzula); (root hairs from short cells); endodermoid layer +; culm bundles in rings; SiO₂ bodies 0 (sand - Juncus); (leaves [spirally] two-ranked); sheath usu. open (auriculate; ligule +), often unifacial; (flowers single); (flowers 2-merous; imperfect), (T large - Marsippospermum), tapetal cells uninucleate, pollen ulcerate, (placentae parietal), 1 basal to many central ovules/carpel, (outer integument 4 cells across - Juncus), funicular obturator [hairs] and hypostase +/0, style branched (styles separate), stigma elongate; seed with (mucilaginous) exotesta and endotegmen; endosperm helobial; phanomer [photosynthetic unifacial cotyledonary hyperphyll] (0), hypocotyl +; n = 3 or more.

7[list]/430: Juncus (300: paraphyletic), Luzula (115). Worldwide, esp. Andes (3 endemic genera), S. South America-New Zealand (2 genera) (Map: Vester 1940; Hultén 1961; Balsev 1996, still incomplete).

• Juncaceae are glabrous (Luzula excepted) caespitose herbs that can be recognised by their solid, rounded stems, leaves that are also often rounded and have open sheaths, and pentacyclic flowers with a scarious perianth.[Photo - Juncus Inflorescence] [Photo - Luzula Flower]

Stem-group Juncaceae are dated to ca 88 million years before present, the crown group diverge ca 74 million years before present (Janssen & Bremer 2004).

In Luzula stamens are opposite individual tepals (Payer 1857).

Some information is taken from Balslev (1998); for anatomy, see Cutler (1969), for some chemistry, see Williams and Harborne (1975), for a family monograph, see Kirschner et al. (2002a-c); for a phylogeny, with Juncus perhaps paraphyletic, see Drábková et al. (2003) and Roalson (2005). See also the World Checklist of Monocots.

CYPERACEAE Jussieu, nom. cons.   Back to Poales

(Vesicular-arbuscular mycorrhizae +); aurones, flavonoid sulphates, flavone C-glycosides, tricin, kestose and isokestose storage oligosaccharides [fructans] +; (velamen +); SiO₂ bodies smooth, conical, with pointed apices, attached to walls; guard cells dumb-bell shaped; cuticular waxes as aggregated rodlets; leaves (two-ranked; tetrastichous; spiral; petiole + lamina), sheath with (contra)ligule; plants monoecious or polygamous; stems solid; inflorescence a panicle of spikelets; T (connate), variously reduced, A (1-)3(-6 or more), (connate), tapetal cells bi-multinucleate, pollen (2-celled), pseudomonads, with distal pore [ulcus](G [2]), (gynophore +), 1 basal ovule/flower, micropyle?, micropylar obturator +, style branches long; fruit an achene, (with bristles, etc.); testa and tegmen thin, ± coalescent, exotesta with SiO₂ bodies, other testal layers fibrous; endosperm nuclear; (mesocotyl +), coleoptile +; n = ³5, -> 55, 56; 3 bp 5.8S nrDNA insertion, rps14 gene to nucleus, pseudogene remaining in mitochondrion.

98[list]/4350. World-wide (Map; Hultén 1961; Vester 1940). [Photo - Carex Carpellate Inflorescence, Eleocharis Spikes.]

1. Mapanioideae

Flowers pseudanthia, with stamens in axils of bracts surrounding carpellate flowers[???].

6/140: Mapania (80), Hypolytrum (50). Largely tropical.

Synonymy: Mapaniaceae Shipunov

2. Cyperoideae

T = scales, bristles, 0 (inner tepals clawed), pollen obovoid, also with 3-6 lateral pores/colpi (pantoporate).

92/4210: Carex (1776: paraphyletic, see Yen & Olmstead 2000; Starr et al. 1999, 2004; Waterway & Starr 2008 - genera like Kobresia, Cymophyllus and Uncinia perhaps to be included), Cyperus (300: paraphyletic, see Muasya et al. 2002), Fimbristylis (250), Rhynchospora (250), Scirpus (200), Scleria (200), Eleocharis (120), Bulbostylis (100), Schoenus (100), Isolepis (70). Worldwide.

Synonymy: Kobresiaceae Gilly, Papyraceae Burnett, Scirpaceae Batsch

• Cyperaceae are herbs with solid, sharply three-angled stems and leaves with closed sheaths. The flowers are very reduced and often aggregated into spikes or heads, the perianth, when recognisable, is scarious, and the fruit is an achene.

Stem-group Cyperaceae are dated to ca 88 million years before present, the crown group diverged ca 76 million years before present (Janssen & Bremer 2004). Smuts (Ustilaginales) are very diverse here (Kukkonen & Timonen 1979; Savile 1979b). About one third of the family have C₄ photosynthesis, with multiple origins within the family as well as some reversals to C₃, and it is possibly involved in increasing the efficiency of the use of nitrogen in plants with submerged leaves (Soros & Bruhl 2000; Bruhl & Wilson 2008). Fruit dispersal mechanisms are remarkably varied, including water, wind (e.g. the bristles surrounding the fruits of Eriophorum), animals (both epi- and endozoochory), and ants (Allessio Leck & Schütz 2005: they also discuss seed dormancy and germination requirements). A few taxa like Rhynchospora anomala are desiccant-tolerant and arborescent; their adventitious roots, which make up the trunk along with the persistent leaf bases through which these roots run, have a well-developed velamen (Porembski 2006). A number of Cyperoideae (but not Scirpeae) have dauciform roots, carrot-shaped roots which develop a dense covering of very long root hairs; these are believed to help in phosphorus uptake by the plant when growing in phosphorus-poor soils (Shane et al. 2005: some Juncaceae may also have such roots). epidermal cells in such roots are elongated at right angles to the long axis of the root (Shane et al. 2005).

Zhang et al. (2004) have recently shown that spikelet structure in Schoeneae, at least, is sympodial, although that of Cyperoideae is indeterminate (Vrijdaghs et al. 2005c). The stamens are shown as being opposite the outer perianth whorl (Bruhl 1991) or the angles of the gynoecium (Goetghebeur 1998). Scirpus sylvaticus has a relatively unspecialised flower in which the three stamens and the carpels are opposite the outer perianth members (Vrijdaghs et al. 2005a). Eriophorum (Cyperoideae) has its distinctive hairs arising centripetally on a perianth ring-primordium (Vrijdaghs et al. 2004b). For the literature on the possible pseudanthial nature of some flowers in Cyperaceae, seee Bruhl (1991), who found that the non-sporiferous structures in the taxa he studied were ouside the stamens, so probably representing perianth parts (see also Vrijdaghs et al. 2004a; Richards et al. 2005 - flowers of Exocarya sclerioides [a mapaniid] pseudanthial). The median carpel in Carex is adaxial (Eichler 1875), i.e. in the inverted position (see also Spichiger et al. 2004).

Mapanioideae are sister to the rest of the family, while Carex, sister to Eriophorum, is embedded in Cyperoideae, the other clade (Simpson et al. 2003, esp. 2008). Within Cariceae, phylogenetic studies are beginning to resolve relationships (Yen et al. 2000; Roalson et al. 2001; Starr et al. 2004, 2006; Waterway & Starr 2008). Carex itself includes a few other genera, and conventional wisdom in which a highly compound inflorescence is the plesiomorphic condition for the genus, taxa with simple branches being derived, perhaps several times, seems the exact opposite of what actually happened (Ford et al. 2006; see also Waterway & Starr 2008); again, evolution is not necessarily complex -> simple!

For nomenclature, etc., see Goetghebeur (1985), for a vast amount of general information, see Bruhl (1995), for the prophyll, see Blaser (1944), for floral morphology, see Goetghebeur (1998), for pollen, see van Wichelen et al. (1999), for the gynophore, etc., see Vrijdaghs et al. (2005b), for propagule dispersal, see Allessio Leck and Schütz (2005), for generic limits, see Muasya et al. (2006), for phytoliths, see Piperno (2006), for chromosome evolution, see Hipp (2007) and Roalson et al. (2008a), for inflorescence morphology, see Vrijdaghs et al. (2008), and for the nrDNA insertion, see Starr et al. (2008); see also the World Checklist of Monocots (Govaerts et al. 2007 is a printed version of this) and Carex interactive identification key by T. M. Jones.

[[Anarthriaceae [Restionaceae + Centrolepidaceae]] [Flagellariaceae [Joinvilleaceae [Ecdeiocoleaceae + Poaceae]]]]: plant rhizomatous; flavones +; primary cell wall also with(1-3,1-4)-ß-D-glucans; sieve tube plastids with cuneate and other less densely packed crystals; (chlorenchyma with peg cells [cf. arm cells of some Poaceae?]); leaves two-ranked, with sheath; bracteoles 0; flowers small, imperfect, T membranous, undifferentiated, endothecial wall thickenings girdle-like, scrobiculate [minute pores penetrating tectum and foot layer], monoporate, annulate ["ulcerate"], 1 apical straight [atropous] ovule/carpel, style branches long, stigmas plumose, receptive cells on multicellular branches; collar rhizoids +.

This clade begins to diversify ca 109 million years before present, originating at ca 112 million years before present (Janssen & Bremer 2004), but note that in their study the topology of this part of the Poales differs from that in the tree above, while Wikström et al. (2001) suggest an origin only 49-45 million years before present, but again the topology of the tree from which this estimate was taken is rather different from that shown here.

A recent analysis of variation in 26S rDNA suggests that Dasypogonaceae may be part of this clade, being very closely linked with Ecdeiocoleaceae, Anarthriaceae and Centrolepidaceae (Neyland 2002b), slightly less so with the one member of Restionaceae included. However, data from atpB, rbcL, and 18S etc., do not suggest such a grouping, so pending further study Dasypogonaceae remain unplaced at the base of the commelinids (q.v. for further discussion). Davis et al. (2004: very weak support) found Flagellaria to group with Mayacaceae, etc., rather than with the other familes of the clade recognised here, while Graham et al. (2005) obtain a set of relationships [Flagellariaceae [Restionaceae [Ecdeiocoleaceae [Poaceae]]], perhaps a branch length or sampling problem.

This is a notably speciose clade (Magallón & Sanderson 2001) with over 10,000 species. However, there is considerable asymmetry in family size within the clade, with most species belonging to Poaceae, the second most species-rich family (Restionaceae) having only some 520 species. Furthermore, given the number of species-poor clades that are successively immediately sister below the PACCMAD and BEP clades (Poaceae) - five - diversification is perhaps more properly described as diversification in the PACCMAD and BEP clades within Poaceae (see also Linder & Rudall 2005 for diversification).

Flagellariaceae have "multicellular papillae" on their stigmas (Appel & Bayer 1998), whether these are receptive in the same way as the multicellular branches of, say, Poaceae, needs clarification. Note that in Poaceae, although the style is hollow, the pollen tubes grow between elongate transmitting cells of these multicellular branches (Lersten 2004). The ovule is scored as lacking a parietal cell and as being tenuinucellate and the pollen as being trinucleate for the whole group by Givnish et al. (1999, cf. Appel & Bayer 1998 for these characters). Joinvilleaceae in particular are largely unknown.

Information on the ORF 2280 region is taken from Hahn et al. (1995) and Katayama and Ogihara (1996), Ecdeiocoleaceae not included), and data on polysaccharide wall composition (mixed-linkage glucans) can be found in Smith and Harris (1999: Joinvilleaceae not included) and Popper and Fry (2004: detected in members of Poaceae and Flagellariaceae, but not in Restionaceae, Juncaceae, and Cyperaceae [the only other Poales examined], nor in any other vascular plants). For the flavonoids of Anarthriaceae, Restionaceae and Ecdeiocoleaceae, see Williams et al. (1997); the variation is complex and needs to be reevaluated in light of the changed position of the last family. Linder and Ferguson (1985) discuss variation in pollen morphology.

Anarthriaceae [Centrolepidaceae + Restionaceae]: root hairs originating from any epidermal cells; chlorenchyma with peg cells; plant dioecious; A 3, opposite inner P, dorsifixed; phanomer [photosynthetic unifacial cotyledonary hyperphyll] +.

ANARTHRIACEAE D. F. Cutler & Airy Shaw   Back to Poales

(Flavonol glycosides +); root hairs lignified; SiO₂ 0; stomata in grooves; leaves ligulate; plant dioecious, culm branched, inflorescence racemose; staminate flowers: pollen operculate; carpellate flowers: G opposite outer P, hypostase +; seed coat?; endosperm type?, embryo?; ?collar rhizoids; n = 6, 9, 11; ORF 2280 +, trnL gene with 3bp deletion and 5bp insertion.

3[list]/11. West Australia (Map: from FloraBase 2004). [Photo - Anarthria Staminate & carpellate inflorescences © D. Woodland]

Stem-group Anarthriaceae are dated to ca 96 million years before present, the crown group diverge ca 55 million years before present (Janssen & Bremer 2004).

The three genera are distinctive. Anarthria has equitant leaves, stomata in grooves, a deciduous spathe, and n = 11. Hopkinsia has G 1, with long branches on the style; the fruit is a nut with a fleshy pedicel and persistent perianth, and n = 9; the cotyledon is apparently not photosynthetic. Lyginia has fructans, the culm is unbranched, the stamens are connate, the seeds are minutely spiny with a central hyaline flange, and n = 6. Hopkinsia + Lyginia are sister taxa - they have a culm with subepidermal chlorenchyma separated from cortex by parenchymatous and sclerenchymatous rings; leaves reduced to scales; pollen microverrucate - and are associated with Anarthria (Briggs et al. 2000, see also papers in Meney and Pate 1999). However, the sampling of non-Australian Restionaceae is poor, and Linder et al. (2000) even suggest they are Restionaceae, albeit perhaps sister to the rest - they have the distinctive culm anatomy of the family, and Lyginia has starch in the embryo sac, like Restionaceae (Hopkinsia is unknown). Stigma papillae in Anarthria? Microsporogenesis?

Much information is taken from Briggs and Johnson (2000); note that no comparison is made there with Ecdeiocoleaceae and no hierarchical information is conveyed by having three families for three genera. Other information is taken from Cutler and Airy Shaw (1964), Linder and Rudall (1993) and Linder et al. (1998).

Synonymy: Hopkinsiaceae B. G. Briggs & L. A. S. Johnson, Lyginiaceae B. G. Briggs & L. A. S. Johnson

Centrolepidaceae + Restionaceae: anthers bisporangiate/monothecal, embryo sac with compound starch grains, cells of nucellar epidermis anticlinally elongated.

CENTROLEPIDACEAE Endlicher, nom. cons.   Back to Poales

± Caespitose herbs; vessels in stem and leaf; SiO₂ ?0; plants monoecious; epidermis with hairs and papillae; leaves unifacial (ligulate); inflorescence scapose, capitate and with inflorescence bracts or spicate; "flowers" ?pseudanthia or not, P 0; staminate flowers: A 1, pollen pore not annulate; carpellate flowers: G [5], antipodals usu. binucleate, nucellar cap 0, stigma?; fruit abaxially dehiscing or indehiscent; endotegmen persistent, tanniniferous; embryo conoid; (phanomer 0), first seedling leaf with lamina, chlorenchymatous cells isodiametric or palisade; n = 10.

3[list]/35. Hainan, IndoChina and Malesia to New Zealand, S. South America (Gaimardia) (Map: from Ding Hou 1957; Hamann 1960; van Balgooy 1984; FloraBase 2004). [Photo - Gaimardia Habit and Close-up, Centrolepis Habit.]

• Centrolepidaceae are rather small more or less caespitose herbs. The inflorescence is scapose and spicate or capitate and involucrate.

The age of the Centrolepidaceae clade ranges from 45-97 million years before present depending in large part exactly where it is placed in this part of the tree (Janssen & Bremer 2004).

Centrolepidaceae may be neotenous Restionaceae, but their position with regard to that family remains uncertain (e.g. Linder et al. 2000); most studies unfortunately concentrate on either the Australian or African Restionaceae and broader studies are needed. As things stand, a position sister to Restionaceae is possible (Linder & Caddick 2001) as well as one - but with weak support - within the family (Bremer 2002). It may be relevant that the pollen apertures of Australian Restionaceae in particular are like those of Centrolepidaceae (Chanda 1966).

Cutler (1969) emphasized the fact that the root hairs arose from one side of the epidermal cell and that the root lacked a pericycle. He suggested that the peg cells of Centrolepidaceae and Restionaceae might be rather different, peg cells sensu stricto perhaps being absent in the former. Also, whether or not the family has SiO₂ bodies needs confirmation. The carpels of the separate flowers sometimes become more or less fused, the result being something that looks like a syncarpous gynoecium - or, in Centrolepis itself, the gynoecium is definitely syncarpous, the carpels appearing to be more or less one on top of each other being the result of developmental gymnastics.

The ovule is described by Hamann (1975) and Cooke (1998) as being weakly crassinucellate and also as having a megasporocyte that lacks a parietal cell; perhaps cells in the nucellar epidermis have divided. Hou (1957) described the anthers as being 1- or 2-celled.

RESTIONACEAE R. Brown, nom. cons.   Back to Poales

Flavonols, glycoflavones, (8-hydroxyflavonoids, e.g. gossypetin - Australian taxa]) +; root hairs usu. persistent, lignified; rhizome with endodermoid sheath; stem with complete cylinder of sclerenchyma, bundles inside, both peripheral and medullary; vessels in stem (and leaf); SiO₂ bodies not epidermal (0); leaves much reduced (sheath closed); plant di(mon)oecious, flowers in spikelets or solitary and with bracteoles; outer T hooded [?how common], (P 0), staminate flowers: (anthers tetrasporangiate, e.g. Harperia), tapetal cells 1-4-nucleate, pollen (binucleate), (pore not annulate), with coarse granules [exine fragments] on pore; carpellate flowers: P variable, G opposite outer P, (only 1 fertile), (ovules crassinucellate - Alexgeorgea; micropyle endostomal - Willdenowia, some Leptocarpus), large starch bodies surrounding polar nuclei, (antipodals proliferating), hypostase +, style short or 0 (only 1 branch); (fruit a nut); (seed with elaiosomes), exotesta persistent; n = 6, 7, 9, 11, 12 [Australia], 16, 20 [Africa]; (cotyledon not photosynthetic), hypocotyl and collar at most small, collar rhizoids +, first seedling leaf with lamina; 28 kb chloroplast genome inversion +/- [latter - Desmocladus, Elegia?].

58[list]/520: Restio (90), Ischyrolepis (50), Elegia (35), Thamnochortus (35). Africa (inc. Madagascar), esp. the S.W., Hainan and Vietnam to New Zealand, esp. S.W. Australia, Chile (Apodasmia) (Map: from Good 1974). [Photos - Collection. Dovea tectorum is properly Chondropetalum tectorum] [Photo - Elegia Habit]

• Restionaceae are sometimes quite large herbs with very much reduced leaves; the flowers are small, imperfect but usually with a perianth, and aggregated into spikelets.

Stem-group Restionaceae are dated to ca 96 million years before present, the crown group diverge ca 74 million years before present (Janssen & Bremer 2004). There are ca 350 spp. of Restionaceae in the Cape region, diversification beginning in the late Eocene-early Oligocene some 43-28 million years before present (Hardy et al. 2004; Linder & Hardy 2004; Hardy et al. 2008). Restionaceae can be locally dominant in oligotropic conditions, whether wet or dry. The habitats they prefer are often subject to seasonal fires, and some species, sprouters, accumulate starch in their rhizomes, while others, non-sprouters, reproduce by seeds (cf. Ericaceae). The rootlets of Restionaceae are also described as being capillaroid, with dense and exceptionally long root hairs, although there are other distinctive morphologies (Lambers et al. 2006); Cyperaceae and Proteaceae growing in similar phosphorus-poor environments develop analagous structures that are beleived to facilitate phosophorus uptake by the plant. [What is the relationship with lignification of root hairs?]

The culm has subepidermal chlorenchyma separated from the cortex by parenchymatous or sclerenchymatous rings; these may not be strictly comparable (Cutler 1969) and so may not be an apomorphy for the family.

South African Restionaceae: flavonols common, (myricetin), proanthocyanidins +, flavones less diverse; ridges of sclerenchyma alternate with vascular bundles; protective cells [lignified chlorenchymatous cells lining subepidermal cavities] +; pollen grains with 4-10 pores, margins of pores annulate [raised]. Australian Restionaceae: flavonols rare, except quercetin, proanthocyanidins rare, flavones diverse, sulphated flavonoids +; pollen pores 8-25, not annulate (cf. also Centrolepidaceae!); cotyledon not photosynthetic [ca half the genera], seedling culm internodes elongated, leaves terete (not - Anthochortus), chlorenchymatous cells palisade [latter set of characters need checking] - probably paraphyletic.

The variation in the presence of the 28kb chloroplast genome inversion within Restionaceae is remarkable (Michelangeli et al. 2003); is the family polyphyletic?!

Information is taken from Kircher (1986; he does not draw the guard cells as being dumbbell-shaped), Linder et al. (1998: general), Meney and Pate (1999), Linder and Caddick (2001: esp. seedlings), Ronse Decraene et al. (2001a, 2002b: floral development, much variation) and Newton et al. (2002: seeds). Williams et al. (1998) and Harborne et al. (2000) describe flavonoid patterns in the family. For Peter Linder's "Intkey thingy" on African Restionaceae - 2,000 pictures - see http://www.systbot.unizh.ch/datenbanken/restionaceae/.

Synonymy: Elegiaceae Rafinesque

Flagellariaceae [[Joinvilleaceae + Ecdeiocoleaceae] Poaceae]: trichoblasts from distal cell of pair; leaf blade with cross veins, ligule +; inflorescence paniculate, branches with adaxial swellings; fruit indehiscent, fleshy; cotyledon not photosynthetic.

Net venation, animal-dispersed propagules and tolerance of shady habitats are linked in this group (Givnish et al. 2005).

Bremer (2002) found a sister group relationship between Ecdeiocoleaceae and Poaceae, as had Harborne et al. (2000), although the latter did not include Joinvilleaceae and Flagellariaceae in their study. A combined morphological and molecular (mitochondrial and chloroplast genes) analysis placed Flagellariaceae, Ecdeiocoleaceae and Poaceae in an unresolved trichotomy (Michelangeli et al. 2002), a not dissimilar result to that obtained by Davis et al. (2004). However, in another two-gene study, although both genes were chloroplast genes, Marchant and Briggs (2007: both genera of Ecdeicoleaceae included) found strong support for a sister group relationship between Joinvilleaceae and Ecdeiocoleaceae. Monophyly of the whole clade, and other relationships in it, were also strongly supported.

For the scoring of cross veins in the leaf, see Soreng and Davis (1998). For alternating long and short cells, see Stevenson in Michelangeli et al. (2003). In the interpretation of floral morphology of Ecdeiocoleaceae I follow Rudall et al. (2005a) and especially Whipple and Schmidt (2006); see also the discussion after Poaceae. Although both crassi- and tenuinucellate ovules are reported for grasses, Rudall et al. (2005a) suggest that the reports of the former need confirmation.

FLAGELLARIACEAE Dumortier, nom. cons.   Back to Poales

Dichotomising stem apices; flavonols +; endodermis radially elongated; SiO₂ associated with bundles only; neighbouring cells of stomata with oblique divisions; prophylls lateral; leaves with terminal tendril, base ?auriculate, sheath also closed; P pseudo-uniseriate, pollen 2-nucleate, ovule crassinucellate, micropyle endostomal, embryo sac bisporic, eight nucleate [Allium-type], style solid; fruit a drupe, seed coat adnate to fruit, exotestal; n = 19; ORF 2280 present?; seedling with collar hairs +, coleoptile at most short.

1[list]/4. Palaeotropics, to the Pacific Islands (Map: van Steeenis & van Balgooy 1966; Heywood 1978). [Photo - Flower]

• Flagellariaceae are robust, climbing or scrambling rather grass-like plants that can be recognised by their leaves that terminate in a sensitive tendril by which the plant is attached to its support. The rather large, paniculate inflorescences have many small, perfect flowers.

Flagellariaceae may be ca 108 million years old (Janssen & Bremer 2004: but note the topology).

Flagellaria indica may have dichotomising stem apices (Tomlinson & Posluszny 1977).

There is disagreement as to whether or not the ORF 2280 is present - or perhaps there is variation... (cf. Hahn et al. 1995 and Katayama & Ogihara 1996). The stigma has "multicellular papillae". Since the seed coat is adnate to the fruit wall, I suppose the fruit is a caryopsis s. l....

Some information is taken from Rudall and Linder (1988: embryology), Tillich (1996), Appel and Bayer (1998: general), Tillich and Sill (1999: general), and Sajo et al. (2007: style).

[Joinvilleaceae + Ecdeiocoleaceae] Poaceae: SiO₂ bodies cubic; epidermis with microhairs; foliar epidermis with long and short cells [latter SiO₂-containing]; guard cells dumbbell-shaped; fusoid cells [large colorless cells in central mesophyll] +; stem hollow [level?]; endothecial cells with girdle thickenings [?Poaceae], nucellar cap +; first seedling leaf lacking lamina [possible]; 28 and 6.4 kb chloroplast genome inversion +.

This clade may have originated ca 103 million years before present (Janssen & Bremer 2004), although note that Flagellariaceae are not associated with it in that analysis; it diversified only ca 90 million years before present.

The microhairs are multicellular in Joinvilleaceae and some Poaceae. Ecdeiocoleaceae, a small family of small herbs, has recently been placed in this clade (see below). If their seedlings have leaf blades, they may provide a valuable source of data on epidermal anatomy. For chloroplast genome inversions, see Doyle et al. (1992); the 6.4 kb inversion has recently been reported in Ecdeiocoleaceae (Michelangeli et al. 2002, 2003; Marchant & Briggs 2007).

Joinvilleaceae + Ecdeiocoleaceae: unknown.

JOINVILLEACEAE Tomlinson & A. C. Smith   Back to Poales

Arm cells 0; leaves plicate, auriculate or ligulate; flowers perfect, outer T hooded, ovule type?, embryo sac bisporic; fruit a drupe, P persistent; n = 18; rps14 gene to nucleus, pseudogene remaining in mitochondrion; first seedling leaf lacking lamina.

1[list]/2. Malay Peninsula to the Pacific (Map: from van Steenis & van Balgooy 1966; Newell 1969). [Photo - Habit, Flower.]

• Joinvilleaceae are robust, grass-like plants with plicate leaves and terminal panicles of small, perfect, brownish flowers.

Joinvilleaceae may be some 90 million years old (Janssen & Bremer 2004).

The outer tepals may have only a single trace (Newell 1969).

Some information is taken from Newell (1969: revision) and Bayer and Appel (1998: general).

ECDEIOCOLEACEAE D. F. Cutler & Airy Shaw   Back to Poales

SiO₂ as sand; vessels?; stomata in grooves; leaves reduced, sheath closed, auriculate; plant monoecious, culm branched, inflorescence branch swellings?, with "spikelets"; P 2 conduplicate and keeled + 4 flat, staminate flowers: A 4 [Ecdeiocolea], pollen with operculum, wall without scrobiculi, with intraexinous channels; carpellate flowers: (embryo sac tetrasporic - Ecdeiocolea); fruit 1-seeded, achene or capsule; ?perisperm +; exotestal cells large; n = ca 24, 32, 33; seedling?

2[list]/3. S.W. Australia (Map: from FloraBase 2004).

Stem-group Ecdeiocoleaceae are dated to ca 89 million years before present, the crown group diverge ca 73 million years before present (Janssen & Bremer 2004).

In Georgeantha only the two adaxial calyx members are keeled, while in Ecdeiocolea the differentiation is somewhat less pronounced. The flowers of Ecdeicolea are monosymmetric; the four stamens probably represent the outer whorl plus the adaxial stamen of the inner whorl (Rudall et al. 2005a). The exotesta is very differently thickened in the two genera, and the fruits are quite different.

Some information is taken from Briggs and Johnson (1998), Linder et al. (1998) and especially Rudall et al. (2005a: floral development, fruits).

POACEAE Barnhart, nom. cons.//GRAMINEAE Jussieu, nom. cons. et nom. alt.   Back to Poales

Vesicular-arbuscular mycorrhizae +; 3 desoxyanthocyanins, flavone 5- and C-glycosides, tricin, flavonoid sulphates, (cyanogenic glycosides) +; primary cell wall rich in arabinoxylans, pectin 10³%, xyloglucans lacking fucose; sieve tube plastids also with rod-shaped protein bodies, P-proteins 0; cuticle waxes as aggregated rodlets; leaves pseudopetiolate, supervolute(-plicate), midrib +; two adaxial outer T distinct, abaxial smaller; staminate flowers: pollen with operculum, wall without scrobiculi, with intraexinous channels; carpellate flowers: A?, G with 1 central amphitropous or hemianatropous crassinucellate ovule [funicle short], micropyle endostomal, supernumerary antipodals +, style solid [?level]; fruit an achene, the testa closely adherent to pericarp [= caryopsis], hilum long [reverses]; peripheral layer of endosperm meristematic, embryo lateral, long, well differentiated, plumule lateral; primary root 0, collar [epiblast, the ligule of the cotyledon] conspicuous; n = ?; expansion of the inverted repeat [level?], trnT [third!] inversion in the single copy region of the chloroplast genome, duplication of AP1/FUL genes [= FUL1 and FUL2], rps14 gene to nucleus, pseudogene remaining in mitochondrion, intragenomic translocation of chloroplast rpl23 gene.

668/10035. Thirteen subfamilies below. Worldwide (Map: from Vester 1940; Hultén 1961). [Genera List] [Photo - Flower]

1. Anomochlooideae Potzdal

Pseudopetiole with an apical pulvinus; ligule as a fringe of hairs; inflorescence branches cymose, two "bracts" along each branch unit, two more "bracts" below each flower; P 2 (3) + 3, anthers centrifixed [Anomochloa]; or flowers spirally arrranged along racemose axis, with several spiral "bracts" below each flower, A subasifixed, basally connate [Streptochaeta], n = 11, 18; first seedling leaf lacking lamina.

2/4. Central America to S.E. Brasil, scattered, forests (Map: from Judziewicz et al. 1997).

This clade is sometimes described as lacking a ligule (Judziewicz & Clark 2008, which see for other distinctive characters), or the ligue is described as being represented by a ring of hairs...

Synonymy: Anomochloaceae Nakai, Streptochaetaceae Nakai

Pharoideae + Puelioideae + PACCMAD + BEP clades [the spikelet clade]: leaves with ligules; inflorescence of laterally compressed, racemose, pedunculate spikelets, few-flowered units with two sterile basal bracts [= glumes, spikelet bract + prophyll], flowers two-ranked, each with lemma and palea [?= bract and 2 adaxial connate outer-whorl tepals]; lodicules [inner whorl?] 3 [median member adaxial]; n = 12; 1 bp deletion in the 3' end of the mat K gene.

2. Pharoideae L. G. Clark & Judziewicz

Microhairs 0; leaves resupinate, lateral veins oblique; plants monoecious; spikelets 1-flowered; A 6, anthers centrifixed, wall of the Reduced type, micropyle bistomal [Pharus]; coleoptile [= first seedling leaf] with lamina.

3/14. Pantropical, in forests (Map: from Judziewicz 1987; Judziewicz et al. 1997).

The style is hollow in Pharus. In addition, the anther wall consists solely of epidermis and endothecium (i.e. it is of the Reduced type), the latter degenerating before anthesis (Sajo et al. 2007); Pharus has numerous distinctive features that need to be integrated with the phylogenetic tree. See also Judziewicz and Clark (2008)

Synonymy: Pharaceae (Stapf) Herter

Puelioideae + PACCMAD + BEP clades [the bistigmatic clade]: phytoliths saddle-shaped; spikelets disarticulating above the glumes; stigmas 2, two orders of stigmatic branching; 15bp ndhF insertion.

3. Puelioideae L. G. Clark, M. Kobay., S. Mathews, Spangler & E. A. Kellogg

Characters?; A 6; seedling leaf unknown.

2/11. Tropical Africa (Map: from Emmet Judziewicz, pers. comm.).

PACCMAD + BEP clades: (ergot alkaloids [synthesized by endophytes] +); arm and fusoid cells 0; foliar cross veins 0; pseudopetiole 0; A 3, lodicules 2, G 2, styles separate; x = 12; 15 bp insertion in ndhF gene, disease resistance by the Hm 1 gene. Mostly non-forest.

The age of this clade may be ca 90 million years (Kellogg 1999).

For the Hm 1 gene, see Sindhu et al. (2008).

Panicoideae + Arundinoideae + Centothecoideae + Chloridoideae + Micrairoideae + Aristidoideae + Danthonioideae [PACCMAD clade]: phytoliths dumbbell-shaped; mesocotyl internode elongated, epiblast 0; extension of ndhF gene from the short single copy region into the inverted repeat.

For the ndhF gene, see Davis and Soreng (2008). Ca 50% of the species have C₄ photosynthesis.

[Panicoideae + Centothecoideae] Arundinoideae + Chloridoideae: 6 bp insertion in the 3' end of the mat K gene.

Panicoideae + Centothecoideae: hilum non-linear; overlapping embryonic leaf margins.

The first character could also be used to unite Panicoideae + Arundinoideae + Centothecoideae + Chloridoideae.

For a discussion of the relationships - close, and perhaps even entwined - between Panicoideae and Centothecoideae, see Duvall et al. (2008a) and especially Sánchez-Ken and Clark (2008).

4. Panicoideae Link

(Fusoid cells +); culms usually solid; spikelets dorsally compressed, rachilla 0, 2-flowered, lower flower staminate or sterile [gynoecial cell death caused by Tasselseed2], one carpellate floret, spikelet dispersed as a 1-seeded unit by disarticulation below the glumes; C₄ photosynthesis common; starch grains simple; 5 bp insertion in the rpl16 intron; n = 5 (7) 9, 10 (12, 14); germination flap +; rps14 pseudogene lost.

206/3245: Panicum (500 s.l., but polyphyletic, 100 s. str., Dicanthelium [55] - see e.g. Zuloaga et al. 2007), Paspalum (330), Setaria (150: cf. also Cenchrus), Andropogon (100). Tropics to temperate.

The large tribe Andropogoneae, with almost 1,100 species, can be distinguished from all other graases because they have paired spikelets.

Sorghum and Zea are important grain genera of this subfamily.

Note that details of the mechanisms of C₄ photosynthesis and the morphologies associated with it are very variable in this subfamily, and C₄ photosynthesis has evolved more than once, with similar amino acid changes occuring in parallel in the phosphoenolpyruvate carboxylase gene (Kellogg 2000 and references; see also Christin et al. 2007a, b).

For general information on Paniceae, see Crins (1991), for unisexuality, see Le Roux and Kellogg (1999), for relationships within Panicoideae and C₄ photosynthesis, see Giussani et al. (2001), for relationships in the bristle clade of Paniceae, see Doust et al. (2007), and those within Panicum itself, see Aliscioni et al. (2003), for the phylogeny of Andropogoneae, see Mathews et al. (2002), for inflorescence evolution, see Doust and Kellogg (2002), for the evolution of the NADP-malate dehydrogenase gene following its duplication, see Rondeau et al. (2005).

Synonymy: Andropogonaceae Martynov, Arundinellaceae (Stapf) Herter, Panicaceae Voight, Saccharaceae Martynov, Zeaceae A. Kern

5. Centothecoideae Soderstrom

Mesophyll differentiated into palisade and spongy tissues; chlorenchyma cells lobed [cf. arm cells]; style +; n = (11) 12; epiblast +.

12/32. Warm temperate to tropical forests (Map: from Sánchez-Ken & Clark 2008).

Arundinoideae + Chloridoideae + Aristidoideae + Danthonioideae: ligule hairy; lemma awned; starch grains compound.

Eriachne, with ca 40 species, may be sister to this clade.

Arundinoideae + Chloridoideae: hilum short.

6. Arundinoideae Burmeister

n = 6, 9, 12.

14/20-38. Temperate to tropical, hydrophytic to xerophytic.

The exact contents of this subfamily are still unclear.

Synonymy: Arundinaceae (Dumortier) Hochst.

7. Chloridoideae Beilschmied

Microhairs with inflated distal cells; spikelets disarticulating above the glumes; 4 bp insertion in the rpl16 intron; n = (7, 8) 9, 10; C₄ photosynthesis prevalent.

/1350: Eragrostis (300), Muhlenbergia (160), Sporobolus (160), Chloris (55). Tropical to warm temperate, more or less dry environments especially in Africa and Australia.

The first three genera may be polyphyletic. For a morphological phylogenetic analysis of the subfamily, see Liu et al. (2005). For relationships within Chloridoideae, see papers in Aliso 23: 565-614. 2008.

Apparently the earliest name for this clade is Chondrosoideae Link, which is a sort of resurrection name - Googling it (as of 3.vii.2007) returns only Thorne and Reveal (2007), who are apparently the only people to have used it for some time, and about 42,100 returns for Chloridoideae.

Synonymy: Chloridaceae (Berchtold & J. Presl) Herter, Eragrostidaceae (Stapf) Herter, Pappophoraceae (Kunth) Herter, Spartinaceae Burnett, Sporobolaceae Herter

8. Micrairoideae Pilger

Stomata with dome-shaped subsidiary cells; ligule with fringe of hairs; lemma awn +/0; embryo small, starch grains simple; n = 10; germination flap +; (C₄ photosynthesis - Eriachneae).

8/170: Isachne (100), Eriachne (35). Tropics.

Micraira has spirally arranged leaves and at least some species are resurrection plants.

For further information, see Sánchez-Ken et al. (2007).

Aristidoideae + Danthonioideae: lemma awn trifid, or 3 awns.

9. Aristidoideae Caro

Awns with basal column; n = 11, 12; germination flap +; C₄ photosynthesis prevalent.

3/300-385: Aristida (230-330), Stipagrostis (50). Warm temperate, few in Europe.

10. Danthonioideae Barker & Linder

Prophylls bilobed [?distribution]; synergid cells haustorial, bases of styles well apart; n = 6, 7, 9.

19/270: Danthonia (100), Rytidosperma (90). Widespread, but few Southeast Asia-Malesian, especially southern, Africa.

For a phylogeny of the Pentaschistis group, also character evolution, see Galley & Linder (2007).

Ehrhartoideae [Bambusoideae + Pooideae] [BEP clade]: [?embryo short]; x = 12.

11. Ehrhartoideae Link

(Microhairs 0); fusoid cells 0 (arm cells +); spikelets with only one carpellate floret fertile and with basal carpellate or sterile florets, glumes very small; A (1-)6, styles separate almost from the very base; n = (10, 15).

17/120: Oryza (20), Leersia (20). Widespread, esp. S. hemisphere.

For a phylogeny of Oryzeae, see Guo and Ge (2005), for rice domestication, see Sweeney and McCouch (2007), and for diversification in Oryza, see Zou et al. (2008). The first seedling leaf of Oryzeae does not have a lamina.

Synonymy: Oryzaceae Burnett

Bambusoideae + Pooideae: characters?

12. Bambusoideae Luersson

Woody; fusoid cells and strongly asymmetrically invaginated arm cells +; leaves pseudopetiolate, often with inner and outer ligules, culm leaves often very different from the others; (lodicules 3), A (2-)6(-140), (basally connate), stigmas (1-)2-3; overlapping embryonic leaf margins; first seedling leaf without lamina; n = 7, 9-12.

84-101/940-1320. Bambusa (120), Chusquea (120), Sasa (60), Phyllostachys (55), Arundinaria (50). Tropical to temperate, often in forests.

Diversification within bamboos occured 40-30 million years before present. Woody members are known for their synchronized flowering, even when transported thoudands of miles from their native habitat, and many are monocarpic; this feature is also found in some herbaceous bamboos and, depending on relationships within the subfamily, may even be plesiomorphic for it.

Clark and Triplett (2006) discussed relationships within the Bambusoideae, previously divided into the woody Bambuseae and the herbaceous Olyreae. However, the woody temperate bamboo group may be sister to the rest of the family; the monotypic Buergersiochloa, from New Guinea, is a member of the monophyletic and otherwise entirely New World woody bamboo group, and the Olyreae are derived (e.g. Bouchenak-Khelladi 2008). For a phylogeny of the woody bamboos, but with rather little resolution, see Clark et al. (2008).

For general information, see Clark (1997), Judziewicz et al. (1997), and Judziewicz and Clark (2008), for foliar epidermis, see Yang et al. (2008).

Synonymy: Bambusaceae Burnett, Parianaceae Nakai

13. Pooideae Bentham

Fructose oligosaccharides in stem; microhairs 0; stomata subsidiary cells with parallel sides; primary inflorescence branches distichous; lemma usually with 5 nerves; lodicules at most slightly vascularised, styles separate almost from the very base; hilum often short; n = (2, 4-)7[chromosomes large; core Pooideae](-13); duplication of the ß-amylase gene.

/3300. Festuca (470: inc. Lolium), Poa (200), Stipa (300), Calamagrostis (230), Agrostis (220), Elymus (150), Bromus (100). Largely N. temperate.

Although low levels of fructan accumulation, specifically levans, have been noted in many Poaceae, high levels are found only in Pooideae, but not in taxa of the basal pectinations (see Hendry 1993 for taxa involved; Pollard & Cairns 1991).

Hybridisation, introgression, and polyploidy and rife in Triticeae (e.g. G. Petersen et al. 2006a; Mason-Gamer 2008), which include a number of important grain genera such as Triticum, Hordeum, etc. Genera may not be monophyletic here! For a phylogeny of Poeae, which should now include Aveneae, see Quintinar et al. (2007, also Döring et al. 2007; Soreng et al. 2007), for that of Poa, see Gillespie and Soreng (2005), and for a phylogeny of Stipeae (European Stipa s. str. may be sister to the rest of the tribe which is from Asia-America), see Romashchenko et al. (2007: ?support). Inda et al. (2008) discuss the biogeography of Loliinae, which seems to have invoved multiple dispersal events from a center in the Mediterranean region over the last ca 13 million years. There are several papers on Poooideae in Aliso 23: 335-471. 2008 which should also be consulted, and see Essi et al. (2008) for relationships around Briza.

It is not certain the the duplication of the ß-amylase gene is an apomorphy of (many) Pooideae. One of the copies of the gene breaks down starch into fermentable sugars in the endosperm, while the other is more broadly expressed in the plant, as it is in other Poaceae (Mason-Gamer 2005).

For a catalogue of New World Pooideae, see Soreng et al. (2003).

Synonymy: Aegilopaceae Martynov, Agrostidaceae Burnett, Alopecuraceae Martynov, Avenaceae Martynov, Festucaceae Pfeiffer, Hordeaceae Burnett, Melicaceae Martynov, Nardaceae Martynov, Phalaridaceae Burnett, Stipaceae Burnett, Triticaceae Hochst.

• Poaceae can be recognised by their leaves that have long open sheaths and ligules at the sheath-lamina junction, round and often hollow stems, and inflorescences whose basic unit is a spikelet. Individual flowers are small, lacking an obvious perianth and with a gynoecium that usually has two plumose stigmas and a single ovule. In the dry, achenial fruit (often called a caryopsis), the rather large embryo is lateral, lying next to the seed coat.

Stem-group Poaceae are dated to ca 89 million years before present, the crown group diverge ca 83 million years before present (Janssen & Bremer 2004: Streptochaeta included, see also Bremer 2002; dates in Wikström et al. 2001 are far younger). As to more conventional grasses (the [PACCMAD + BEP] clade), fossil spikelets assignable to them are known from the Palaeocene-Eocene boundary, about 55 million years before present (Crepet & Feldman 1991), and this estimate is broadly in line with an estimate of the age of a genome duplication in Poaceae (70-50 million years before present: Blanc & Wolfe 2004; Schlueter et al. 2004; Paterson et al. 2004). However, Poinar (2004) suggests that Programinis burmitis, from the Early Cretaceous some 100-110 million years before present, is an early bambusoid grass type. Although it has some vegetative features that are common in Poaceae, it does not have distinctive features of the family and so is unlikely to be included here (Caroline Stömberg, pers. comm.). The age of grasses (as well as that of other monocot groups, not to mention the animals, both vertebrates and insects, associated with them) is also questioned by the discovery of well-preserved phytoliths of types to be found in the PACCMAD and BEP clades in coprolites of sauropod dinosaurs from the Late Cretaceous (71-65 million years before present) of central India (Prasad et al. 2005: there are grass pollen and macrofossils also known from this age). This record, too, needs confirmation, although the enigmatic Late Cretaceous mammalian sudamericid gondwanatherians also had hypsodont teeth and there is a record of a hadrosaurian dinosaur with carbon isotope ratios that suggests that it might have been eating C₄ plants (Prasad et al. 2005; Bocherens et al. 1994).

Such fossils aside, C₄ photosynthesis in grasses seems to have been present in grasses from the Early to Middle Miocene in both the Great Plains and Africa, some 25-12.5 million years before present, perhaps initially in response to decli