The grass genera of the world
Habit, vegetative morphology. Robust perennial; rhizomatous. Culms 12–35 cm high; herbaceous; unbranched above. Leaves non-auriculate. Sheath margins free (for at least three quarters of the lengths of the sheaths). Leaf blades linear; narrow; 1–4 mm wide; flat, or rolled (convolute); without cross venation. Ligule an unfringed membrane; not truncate; 0.5–3.5 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; open; espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 18–35 mm long (i.e., large); purplish, papery; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings. Rachilla prolonged beyond the uppermost female-fertile floret; hairless; the rachilla extension with incomplete florets. Hairy callus absent. Callus short; blunt.
Glumes two; very unequal; shorter than the adjacent lemmas; hairless; glabrous; pointed to not pointed; awnless; non-carinate; similar. Lower glume 1–3 nerved. Upper glume 5 nerved, or 7 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped; awnless.
Female-fertile florets 7–9. Lemmas apically rounded or erose; similar in texture to the glumes; not becoming indurated; incised; pointed to blunt; when incised, 2 lobed; not deeply cleft; awnless, or mucronate to awned. Awns when present, 1; median; from a sinus; non-geniculate; hairless; much shorter than the body of the lemma; entered by one vein. Lemmas hairless; scabrous; non-carinate; without a germination flap; 5–7 nerved; with the nerves non-confluent. Palea present; conspicuous but relatively short (about half the lemma length); tightly clasped by the lemma; apically notched; awnless, without apical setae; textured like the lemma; not indurated; 2-nerved; 2-keeled. Palea keels wingless; scabrous. Lodicules present; 2; free; membranous; ciliate, or glabrous; toothed; not or scarcely vascularized. Stamens 3. Anthers 6–7 mm long; not penicillate; without an apically prolonged connective. Ovary apically apically hairy; with a conspicuous apical appendage (fleshy above the styles), or without a conspicuous apical appendage (? - not at all Bromus-like, in material seen). Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Endosperm containing only simple starch grains.
Abaxial leaf blade epidermis. Costal/intercostal zonation lacking. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls (rather thick, pitted). Microhairs absent. Stomata absent or very rare (none seen). Intercostal short-cells common; in cork/silica-cell pairs (frequent pairs, but no silica bodies in the silica cells); not silicified. Costal short-cells predominantly paired (some solitary). Costal silica bodies absent.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs; with the ribs more or less constant in size to with the ribs very irregular in sizes. Midrib not readily distinguishable; with one bundle only. Bulliforms not present in discrete, regular adaxial groups. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with the primaries only, the rest with strands); forming figures (in the primaries). Sclerenchyma all associated with vascular bundles.
Special diagnostic feature. Lemmas not as in Briza (q.v.).
Cytology. Chromosomes large.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae (or Triticodae?); Poeae (?). Soreng et al. (2015): Pooideae; Triticodae; Littledaleeae. 3 species.
Distribution, phytogeography, ecology. Central Asia to western China.
Mesophytic to xerophytic; species of open habitats. Stony slopes.
References, etc. Leaf anatomical: studied by us - L. racemosa Keng.
Special comments. Morphological description revised by E.A. Kellogg, November 1988. Fruit data wanting. Illustrations. • L. tibetica: Hooker’s Ic. Pl. 25 (1892)
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: 11th December 2017. delta-intkey.com/grass’.