The grass genera of the world
Including Puliculum Haines
Habit, vegetative morphology. Perennial (usually), or annual; caespitose, or decumbent. Culms 10–150 cm high; herbaceous; unbranched above; tuberous, or not tuberous. Culm nodes hairy, or glabrous. Culm internodes solid. Leaves not basally aggregated; non-auriculate. Leaf blades linear; narrow; flat; without cross venation; persistent. Ligule present; an unfringed membrane, or a fringed membrane.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality; homomorphic.
Inflorescence. Inflorescence of spicate main branches (very hairy or silky, often brown or purple); digitate, or subdigitate (usually, with a short axis). Primary inflorescence branches 1–20. Inflorescence espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes racemes (spiciform); with very slender rachides; disarticulating; disarticulating at the joints. Articles linear; not appendaged; disarticulating obliquely; densely long-hairy. Spikelets paired; secund, or not secund; sessile and pedicellate; consistently in long-and-short combinations; in pedicellate/sessile combinations. Pedicels of the pedicellate spikelets free of the rachis. The shorter spikelets hermaphrodite. The longer spikelets hermaphrodite.
Female-fertile spikelets. Spikelets compressed dorsiventrally; falling with the glumes (the pedicelled falling from the pedicel, the sessile falling with the joint and pedicel). Rachilla terminated by a female-fertile floret. Hairy callus present. Callus short; blunt.
Glumes two; more or less equal; long relative to the adjacent lemmas; hairy; without conspicuous tufts or rows of hairs; awned (the G1 being rarely bilobed or 2-awned), or awnless; very dissimilar (both villous and rigid to leathery, the lower flattened to depressed on the back and more or less bicarinate, the upper naviculate). Lower glume two-keeled (the keels not winged); flattened on the back to concave on the back; not pitted; relatively smooth; 1–9 nerved. Upper glume 1–5 nerved. Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets proximal to the female-fertile florets. The proximal incomplete florets when present, 1; when present, epaleate; when present, sterile. The proximal lemmas awnless; exceeded by the female-fertile lemmas; similar in texture to the female-fertile lemmas (hyaline); not becoming indurated.
Female-fertile florets 1. Lemmas concurrent with the awn, or bilobed; less firm than the glumes (hyaline); not becoming indurated; entire, or incised; when incised, 2 lobed; when incised, deeply cleft, or not deeply cleft; awned (nearly always), or awnless (in E. manipurensis). Awns 1; usually from a sinus; geniculate; usually hairless; much longer than the body of the lemma. Lemmas hairless; non-carinate; without a germination flap; 1–3 nerved. Palea present, or absent; when present, very reduced; entire; awnless, without apical setae; not indurated (hyaline); nerveless. Lodicules present; 2; free; fleshy; ciliate, or glabrous. Stamens (2–)3. Anthers not penicillate. Ovary apically glabrous. Styles fused, or free to their bases. Stigmas 2; red pigmented.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small; compressed dorsiventrally, or not noticeably compressed. Hilum short. Embryo large. Endosperm containing only simple starch grains. Embryo without an epiblast; with a scutellar tail; with an elongated mesocotyl internode.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present. Intercostal papillae not over-arching the stomata; several per cell (finger-like). Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type; 24–48 microns long; (4.5–)5.4 microns wide at the septum. Microhair total length/width at septum 5.6–7.8. Microhair apical cells 12–29 microns long. Microhair apical cell/total length ratio 0.56–0.8. Stomata common; 19.5–24 microns long. Subsidiaries dome-shaped (low to high), or triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare; not paired (solitary); not silicified. Costal short-cells conspicuously in long rows, or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies panicoid-type; cross shaped, or butterfly shaped, or dumb-bell shaped, or nodular.
Transverse section of leaf blade, physiology. C4; XyMS. PCR cell chloroplasts with reduced grana; centrifugal/peripheral. Mesophyll with radiate chlorenchyma; traversed by columns of colourless mesophyll cells, or not traversed by colourless columns. Leaf blade with distinct, prominent adaxial ribs, or nodular in section, or adaxially flat; with the ribs more or less constant in size. Midrib conspicuous; with one bundle only, or having a conventional arc of bundles. Bulliforms present in discrete, regular adaxial groups; associated with colourless mesophyll cells to form deeply-penetrating fans, or in simple fans and associated with colourless mesophyll cells to form deeply-penetrating fans (sometimes linked with traversing colourless columns, sometimes with large-celled groups of the Zea type). Many of the smallest vascular bundles unaccompanied by sclerenchyma. Combined sclerenchyma girders present, or absent; forming figures, or nowhere forming figures. Sclerenchyma all associated with vascular bundles.
Culm anatomy. Culm internode bundles in three or more rings.
Phytochemistry. Leaves without flavonoid sulphates (2 species).
Cytology. Chromosome base number, x = 5 and 10. 2n = 20 and 40.
Classification. Watson & Dallwitz (1994): Panicoideae; Andropogonodae; Andropogoneae; Andropogoninae. Soreng et al. (2015): Panicoideae; Andropogonodae; Andropogoneae; Saccharinae. 30 species.
Distribution, phytogeography, ecology. Tropical and subtropical Africa, Asia, Australia.
Helophytic to mesophytic; species of open habitats; halophytic, or glycophytic. Grassland, sometimes in moist places, and E. ridleyi in maritime sand.
Economic aspects. Significant weed species: E. villosa. Important native pasture species: E. aurea.
Rusts and smuts. Rusts Puccinia. Smuts from Ustilaginaceae. Ustilaginaceae Sorosporium.
References, etc. Leaf anatomical: Metcalfe 1960; this project.
Illustrations. • E. aurea: Kunth (1835). • E. aurea: Gardner, 1952. • General aspect (E. villosa): Gibbs Russell et al., 1990
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., Macfarlane, T.D., and Dallwitz, M.J. 1992 onwards. The grass genera of the world: descriptions, illustrations, identification, and information retrieval; including synonyms, morphology, anatomy, physiology, phytochemistry, cytology, classification, pathogens, world and local distribution, and references. Version: 13th November 2017. delta-intkey.com/grass’.