史蒂瓦早熟禾 shi di wa zao shu he

Poa gracilior Keng ex L. Liu; P. stewartiana Bor.

Annuals or short-lived perennials. Culms 1 to several, erect or geniculately ascending, (12–)20–50(–70) cm tall, 0.5–0.8 mm in diam., smooth or scabrid below the lower nodes, glabrous, nodes 2–5, 1 or 2 exserted. Leaf sheaths smooth or scabrid or glabrous to strigulose near the collars, 5–15 cm, 1–3 × as long as blade, uppermost closed for 2/5–1/2 of length; blade flat, thin, 3–15 cm × (0.5–)1–2.5 mm, abaxially smooth or scabrid, adaxially and margins densely scabrid, glabrous, apex slender prow-tipped, of tillers up to 10 cm; ligule 0.8–2.5 mm, abaxially smooth, glabrous, apex truncate to obtuse, collar margins sparsely shortly ciliate or glabrous. Panicle open, ovoid, lax, (6–)9–20 × 3–8 cm, longest internodes 3–5 cm; branches ascending, spreading to reflexed, 2 per node, slender, proximally smooth or sparsely scabrid, distally scabrid angled, longest 4–9 cm with (3–)5–10 spikelets in distal 1/3. Spikelets narrowly elliptic, 3–5 mm, florets 2–4; vivipary absent; rachilla internodes to 1 mm, smooth, glabrous; glumes unequal, slender, acuminate, keels slightly convex, sparsely scabrid, surfaces apically smooth or sparsely scabrid, lower glume (2–)3–3.7 mm, 1-veined, upper glume (3–)3.5–4.5 mm, prominently 3-veined; lemmas oblong to elliptic, very thinly papery, 2.5–4.3 mm, ca. 5 × as long as wide, apex slightly acuminate, keel of at least some lemmas pilulose to short villous for 1/3(–1/2) of length, marginal veins for 1/4(–1/3), intermediate veins faint to prominent, areas between veins smooth or minutely bumpy only near base, glabrous; callus sparsely webbed; paleas distinctly shorter than the lemma, smooth, glabrous between keels, keels scabrid, medially sparsely pilulose, area margins narrowly hyaline. Anthers 0.6–1 mm. Fl. and fr. May–Jul.

Grassy places on slopes; 1900–3500 m. W Sichuan, ?Xizang, Yunnan [India (Himachal Pradesh, Uttar Pradesh), Kashmir, Pakistan].

Poa himalayana is the correct name for P. stewartiana Bor, and differs from P. rajbhandarii (P. himalayana sensu Bor and Rajbhandari) by the pilulose palea keels and relatively long glumes, especially the lower ones. It is common in the W Himalayas, but seems to be rare in China. However, as the two species are quite similar and some specimens seem intermediate, they might be better treated as subspecies. It was reported from Yunnan in FRPS (9(2): 145, 153, 154. 2002) under P. himalayana, P. gracilior, and P. stewartiana, but the voucher specimens from Yunnan belong to other species, mainly P. khasiana.