7. Ischaemum thomsonianum Stapf ex C. E. C. Fischer in Gamble, Fl. Madras. 1722. 1934.
尖颖鸭嘴草 jian ying ya zui cao
Ischaemum murinum J. D. Hooker, Fl. Brit. India 7: 135. 1896 ["1897"], not G. Forster (1780).
Annual. Culms slender, shortly stoloniferous at base, branching, 20–45 cm tall, nodes bearded. Leaf sheaths glabrous; leaf blades linear, 2–8.5 × 0.2–0.6 cm, glabrous or a few long tubercle-based bristles toward ligule on adaxial surface, base narrowed or shortly pseudopetiolate, apex setaceously acuminate; ligule 3–5 mm. Racemes terminal and axillary, paired, loosely arranged, 1–3 cm; rachis internodes and pedicels columnar, triquetrous, densely ciliate along angles with yellowish hairs. Sessile spikelet lanceolate, 4.5–5.5 × ca. 1 mm; callus densely bearded, hairs ca. 2 mm; lower glume smooth, glossy, leathery with rounded flanks in lower half, upper half herbaceous, many-veined, bristly, flanks keeled, keels scabrid, wingless, narrowed to bicuspidate apex; upper glume markedly longer than lower, awned, keeled above middle, winged on keel, a tuft of bristles below wing, apex elongate, excurrent into an awn up to 6 mm; awn of upper lemma 1–1.8 cm. Pedicelled spikelet laterally compressed, resembling sessile, bristly, upper lemma awned.
Flatlands; ca. 700 m. W Yunnan [India, Myanmar].
This slender, annual grass is very close to Ischaemum timorense, but has hairier racemes, narrower, hairy spikelets, and longer awned upper glumes than are usual for that species. It may simply be an extreme variant of I. timorense.