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FOC | Family List | FOC Vol. 22 | Poaceae | Poa

31. Poa asperifolia Bor, Kew Bull. [7]. 1952: 130. 1952.

糙叶早熟禾 cao ye zao shu he

Poa megalothyrsa Keng ex Tzvelev.

Perennials, green or grayish green, tufted, rhizomatous, rhizomes fairly stout, short; shoots extra- and intravaginal. Culms erect or decumbent, (35–)40–120 cm tall, 1–2(–2.5) mm in diam., usually several per tuft, nodes (2–)3 or 4, 1 or 2 exserted, smooth, commonly enveloped by fibrous lower sheaths. Leaf sheaths distinctly keeled, smooth or retrorsely scabrid, glabrous, 7–20 cm, 3/4–2 × as long as blade, uppermost closed for 1/4–2/5 of length; blade flat or folded, thin to moderately thin, 7–22 cm (longest at mid-culm), (1.5–)2–5 mm, surfaces scabrid along veins only, margins whitish, densely scabrid, apex slender prow-tipped; ligule hyaline, (2–)3–8 mm, abaxially smooth or sparsely scabrid, apex obtuse, entire or long-lacerate, those of lower culm usually ca. 1 mm or longer, collar margins scabrid, abruptly flared. Panicle open, erect to slightly lax, (9–)13–35 × 4–15 cm, longest internode 2–6 cm; branches ascending to widely spreading, somewhat flexuous, (2–)3–5 per node, fairly slender, proximally rounded to slightly angled, smooth or sparsely scabrid, distally slightly angled, scabrid on and between angles, longest (3–)4–15 cm with (3–)6–26 spikelets in distal 1/2. Spikelets narrowly lanceolate to lanceolate, green, or purple tinged, 4.5–6(–8.5) mm, florets 2–4(–6); vivipary absent; rachilla internodes 0.7–1.5 mm, minutely bumpy, scabrid, or infrequently smooth; glumes unequal, apex acute to acuminate, keel and veins scabrid, area between veins sparsely scabrid, lower glume 2.5–3.5(–4) mm, 1(or 3)-veined, upper glume 3–4.5(–5.4) mm, 3-veined; lemmas lanceolate, elliptic to oblong or obovate, 3.5–4.5(–5.6) mm, apex acuminate, intermediate veins prominent, keel sparsely shortly villous for 1/3 (–1/2) of length, infrequently densely villous or glabrous, marginal veins villous for 1/5(–1/4), proximally densely scabrid to minutely bumpy, glabrous or sparsely pilulose, distally scabrid and minutely bumpy; callus glabrous or occasionally webbed, hairs few and usually short, or infrequently several to 1/2 as long as lemma; palea glabrous, area with slender hooks or crisply pilulose between keels, keels scabrid. Anthers 1.5–3 mm. Fl. and fr. May–Jul.

Fairly common, low alpine to upper forests, openings and thickets on granite, shale, limestone, or sandstone slopes; 3300–4500 m. Gansu, Qinghai, Sichuan, E Xizang, Yunnan [Bhutan].

Poa asperifolia is easily distinguished by the combination of large panicles, long, hyaline, and lacerate ligules, fairly stout, short rhizomes, and fibrous basal sheaths, but its lemma vestiture is highly variable. It approaches P. pratensis through P. lhasaensis (P. jaunsarensis), but differs in having leaf blades very scabrid and often thin, ligules long and lacerate, lemmas minutely hairy or densely scabrid proximally between the veins, and callus glabrous or nearly so. It appears to hybridize with species of P. subg. Stenopoa, but those species lack rhizomes and have more crowded and narrower culms in the regions where they overlap. Tzvelev reported it from SW Xinjiang (Pamirs), but all material seen by us is from the eastern Himalayas and Hengduan Shan, where it is fairly common.


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