The grass genera of the world
Habit, vegetative morphology. Slender perennial; decumbent. Culms 20–25 cm high; herbaceous; branched above. Leaves not basally aggregated; non-auriculate. Leaf blades flat (short); not pseudopetiolate; without cross venation. Ligule an unfringed membrane.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; hermaphrodite and sterile; overtly heteromorphic (the pedicelled member very reduced); all in heterogamous combinations.
Inflorescence. Inflorescence of solitary, shortly peduncled terminal racemes; non-digitate; spatheate (the fragile, spicate racemes partially enclosed by narrow spathes). Spikelet-bearing axes racemes; solitary; with substantial rachides; disarticulating; disarticulating at the joints. Articles non-linear (cuneate); not appendaged; disarticulating transversely; densely long-hairy. Spikelets paired; somewhat 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 sterile (reduced to the G1).
Female-sterile spikelets. The pedicelled spikelet much smaller, reduced to its membranous, nerveless G1.
Female-fertile spikelets. Spikelets 5–6 mm long; slightly compressed laterally; falling with the glumes (deciduous with the adjacent internode and pedicel). Rachilla terminated by a female-fertile floret. Hairy callus present. Callus short; blunt (truncate).
Glumes two; more or less equal; long relative to the adjacent lemmas; free; hairy; without conspicuous tufts or rows of hairs; not pointed (the (G1) obtuse, the G2 notched); the G2 awned (from its sinus); carinate (G2), or non-carinate (G1); very dissimilar (G1 dorsally convex and awnless, G2 cymbiform, awned). Lower glume not two-keeled (wingless, the margins incurved); convex on the back; with a conspicuous pit; relatively smooth; 5 nerved. Upper glume 3 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; sterile (much shorter than the glumes). The proximal lemmas awnless; 3 nerved; decidedly exceeding the female-fertile lemmas; similar in texture to the female-fertile lemmas to decidedly firmer than the female-fertile lemmas (thinly membranous, with broad hyaline margins, entire); not becoming indurated.
Female-fertile florets 1. Lemmas less firm than the glumes (hyaline); not becoming indurated; incised; 2 lobed; not deeply cleft; awned. Awns 1; median; from a sinus; geniculate; hairless; much longer than the body of the lemma. Lemmas hairless; non-carinate; without a germination flap; 3 nerved. Palea present; shorter than the L2; entire (acuminate); awnless, without apical setae; not indurated (hyaline); 2-nerved. Lodicules present; 2; free; glabrous; toothed (conspicuously bidentate). Stamens 3. Anthers not penicillate; without an apically prolonged connective. Ovary apically glabrous. Styles fused. Stigmas 2; red pigmented.
Fruit, embryo and seedling. Fruit not noticeably compressed. Hilum short. Embryo large.
Classification. Watson & Dallwitz (1994): Panicoideae; Andropogonodae; Andropogoneae; Andropogoninae. Soreng et al. (2015): Panicoideae; Andropogonodae; Andropogoneae; Ischaeminae. 1 species.
Distribution, phytogeography, ecology. Thailand and Cambodia.
Species of open habitats.
References, etc. Morphological/taxonomic: Hubbard 1951.
Special comments. Anatomical data wanting.
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’.