The grass genera of the world
Habit, vegetative morphology. Perennial; caespitose. Culms herbaceous; unbranched above. Young shoots intravaginal. Leaves non-auriculate. Leaf blades narrow; setaceous; not pseudopetiolate; without cross venation. Ligule an unfringed membrane; not truncate; 7 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence few spikeleted, or many spikeleted; a single raceme, or paniculate; open; espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets to 25 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret.
Glumes present; two; relatively large; very unequal to more or less equal; about equalling the spikelets; (the longer) long relative to the adjacent lemmas; pointed (acuminate); awnless; non-carinate. Lower glume 5–7 nerved. Upper glume 7–9 nerved. Spikelets without proximal incomplete florets.
Female-fertile florets 4–6. Lemmas similar in texture to the glumes; not becoming indurated; incised; 2 lobed; not deeply cleft (notched); awned. Awns 1; median; from a sinus (flanked by the shortish, narrow acuminate lobes); geniculate; hairless (scabrid); much longer than the body of the lemma. Lemmas hairy; non-carinate; without a germination flap; 7–9 nerved. Palea present; conspicuous but relatively short; apically notched; awnless, without apical setae; 2-nerved; 2-keeled. Lodicules present; 2. No third lodicule. Lodicules free; fleshy; glabrous; not or scarcely vascularized. Stamens 3. Anthers 4.5–5 mm long. Ovary apically hairy (all over). Styles free to their bases. Stigmas 3; white.
Abaxial leaf blade epidermis. Costal/intercostal zonation lacking. Papillae absent. Mid-intercostal long-cells having markedly sinuous walls. Microhairs absent. Stomata absent or very rare. Intercostal short-cells in cork/silica-cell pairs. Costal short-cells predominantly paired. Costal silica bodies rounded and tall-and-narrow; not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Leaf blade with distinct, prominent adaxial ribs; with the ribs very irregular in sizes. Midrib not readily distinguishable; with one bundle only. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming figures. Sclerenchyma not all bundle-associated. The extra sclerenchyma in a continuous abaxial layer.
Classification. Watson & Dallwitz (1994): Pooideae, or Arundinoideae; if pooid, Poodae; if pooid, Aveneae (?); if arundinoid, Danthonieae (?). Soreng et al. (2015): Pooideae; Phaenospermateae. 1 species.
Distribution, phytogeography, ecology. Himalayas.
Species of open habitats. Mountain slopes.
References, etc. Morphological/taxonomic: Macfarlane and Watson 1980. Leaf anatomical: this project.
Special comments. Fruit data wanting. Illustrations. • TS leaf blade of P. himalaica: 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’.