The grass genera of the world
Habit, vegetative morphology. Annual. Culms 5–20 cm high; herbaceous. Leaves non-auriculate. Leaf blades linear; narrow; 0.6–1.2 mm wide; not setaceous; rolled (convolute); without cross venation. Ligule an unfringed membrane; truncate; 1.5 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence unilateral, a single spike, or a single raceme; espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; secund; subsessile.
Female-fertile spikelets. Spikelets 3–6 mm long; compressed laterally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets. Hairy callus absent.
Glumes two; very unequal to more or less equal; (the upper) about equalling the spikelets to exceeding the spikelets; (the upper) long relative to the adjacent lemmas; displaced (the lower displaced to the outside); pointed (subulate-acuminate); awnless; non-carinate. Lower glume 3 nerved. Upper glume 3 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. Spikelets without proximal incomplete florets.
Female-fertile florets 3–6(–9). Lemmas less firm than the glumes (leathery); not becoming indurated; entire; pointed (acute); awned (save for the lowest one or two, which are awnless). Awns 1; median; apical; non-geniculate; entered by one vein. Lemmas hairy, or hairless (sometimes, the lower lemmas only are hairy); non-carinate; without a germination flap; 5 nerved. Palea present; relatively long (subequalling the lemma); apically notched (bidentate); 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; glabrous; toothed; not or scarcely vascularized. Stamens 3. Anthers 0.2–0.3 mm long. Ovary apically glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit slightly adhering to lemma and/or palea; small (2–2.5 mm long); compressed dorsiventrally. Hilum short. Embryo small. Endosperm hard.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (the costals narrow, rectangular); of similar wall thickness costally and intercostally (the walls of medium thickness). Mid-intercostal long-cells more or less rectangular, or fusiform (especially mid-intercostally); having straight or only gently undulating walls. Microhairs absent. Stomata common (mainly adjacent to the costae). Subsidiaries non-papillate; parallel-sided to dome-shaped. Guard-cells overlapped by the interstomatals (and the stomata quite deeply sunken). Intercostal short-cells absent or very rare. Neither prickles nor macrohairs seen, except for the latter at the margin. Costal short-cells neither distinctly grouped into long rows nor predominantly paired (solitary, in pairs and short rows - the intervening long-cells sometimes fairly short). Costal silica bodies present and well developed; horizontally-elongated crenate/sinuous.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll without adaxial palisade. Midrib conspicuous (mainly by its position in the infolded, almost acicular blade, which has only three bundles in the material seen); with one bundle only. The lamina symmetrical on either side of the midrib. Bulliforms not present in discrete, regular adaxial groups (absent). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders absent (each bundle - the midrib and the two laterals - with small adaxial strands only). Sclerenchyma all associated with vascular bundles.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Poeae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Loliinae. 1 species (L. subulatum).
Distribution, phytogeography, ecology. Turkey & Caucasus, East to Baluchistan (Pakistan).
Species of open habitats. Dry places.
References, etc. Leaf anatomical: studied by us.
Illustrations. • L. subulatum: Fl. Pakistan (2016)
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’.