四川早熟禾 si chuan zao shu he

Annuals or short-lived perennials, tufted. Culms 1–60 cm tall, 0.2–1.5 mm in diam., smooth or scabrid below nodes, glabrous, nodes 1–5, 0–3 exserted. Leaf sheaths smooth or scabrid, glabrous, 1–15 cm, slightly shorter than to 2 × as long as blade, uppermost closed for 1/3–1/2 of length; blade flat or infrequently folded, thin, 1–8 cm × 0.5–3(–4) mm, scabrid throughout, apex slender prow-tipped, of tillers 1–15 cm; ligule 0.5–6 mm, abaxially smooth or scabrid, apex truncate to acute, sometimes minutely dentate, collar glabrous. Panicle open, lax, ovoid to pyramidal, included to slightly exserted, (1–)2–20 cm, longest internode (0.5–)1–5 cm; branches ascending to spreading or reflexed, flexuous, 1 or 2(–3) per node, capillary, proximally smooth or scabrid angled, distally scabrid, longest 1–8 cm with 2–20 spikelets in distal 1/4–1/2. Spikelets ovate, green or purple tinged, 2.3–4 mm, florets 2–4(–5); vivipary absent; rachilla internodes 0.5–0.7 mm, smooth or scabrid, glabrous; glumes unequal to subequal, keel scabrid, surface distally scabrid, lower glume 1–2(–2.5) mm, 1(or 3)-veined, upper glume 1.5–2.5(–3) mm; lemmas elliptic, 1.5–2.6(–3.5) mm, apex obtuse to acute, keel scabrid only or pilulose to shortly villous for 1/2 of length, marginal veins for 1/4, veins distally scabrid, intermediate veins prominent, areas between veins minutely bumpy for most of length, sparsely scabrid at least near apex, glabrous; callus glabrous or scantily webbed; palea smooth or minutely bumpy, and sometimes scabrid between keels, keels densely scabrid. Anthers 0.2–0.5 mm. Fl. and fr. May–Sep.

Grassy places among thickets, along forest margins on slopes, natural and disturbed places; (2000–)4700 m. Gansu, Hebei, Qinghai, Shaanxi, Shanxi, Sichuan, Xizang, Yunnan [India (Sikkim), Nepal].

Poa szechuensis, as treated here, includes a highly variable (phenotypically plastic) and strongly inbreeding complex of three varieties. The lemmas of the types of P. szechuensis, P. chumbiensis, and P. tibeti-cola are glabrous, but there are many similar specimens with 1 to several hairs on some lemmas in some spikelets, and we therefore feel justified in applying a broader species concept. All have lemmas mostly 2–2.6 mm and anthers 0.2–0.5 mm.