The grass genera of the world
Habit, vegetative morphology. Perennial; caespitose. Culms 5–15 cm high; herbaceous; tuberous, or not tuberous. Leaves non-auriculate. Sheath margins joined (?). Leaf blades linear; narrow; 0.6–2 mm wide; usually flat; without cross venation; persistent. Ligule an unfringed membrane; 0.8–3.5 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; open (lax, 2–5 branches per node); espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 1.8–4 mm long; compressed laterally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret. Hairy callus absent. Callus short; blunt.
Glumes two; very unequal; shorter than the spikelets; shorter than the adjacent lemmas; awnless; non-carinate (?); similar (lanceolate to ovate). Lower glume 1 nerved. Upper glume 3 nerved.
Female-fertile florets (1–)2–5. Lemmas erose; not becoming indurated; awnless; hairy (in the lower half); non-carinate; without a germination flap; 5 nerved. Palea present; relatively long; 2-nerved; 2-keeled. Lodicules present; 2; free (?); membranous; glabrous; not or scarcely vascularized. Stamens 3. Anthers 1–1.7 mm long. Ovary apically glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit small. Hilum short. Embryo small.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally (thin walled). Mid-intercostal long-cells rectangular; having straight or only gently undulating walls. Microhairs absent. Stomata common. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals (very sunken). Intercostal short-cells common; not paired (solitary); not silicified. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated smooth, or rounded, or crescentic.
Transverse section of leaf blade, physiology. C3; XyMS+. Bulliforms present in discrete, regular adaxial groups; in simple fans. Combined sclerenchyma girders present. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 5, 6, and 9. 2n = 10, 12, and 18. 2 ploid. Chromosomes large.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Poeae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Coleanthinae. 9 species.
Distribution, phytogeography, ecology. Southwestern to central Asia, Himalaya, western China.
References, etc. Morphological/taxonomic: Bor 1970 (under Colpodium). Leaf anatomical: this project.
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’.