Microstegium nudum (Trin.) A. Camus

A very common grass growing on the hills, often in light shade.

Culm tufted, erect or geniculate, about 1 mm across. Blade about 5 cm long by 4 mm wide, glabrous; leaf-base attenuate, petiole-like; sheath sometimes shortly hispid; ligule 0.5-0.7 mm long, chartaceous, rounded on the upper part, hairy on the back. Racemes 3-4, subdigitately arranged, about 4 mm long. Spikelets paired, monomorphic, the upper pedicellate, the lower sessile about 2.5 mm long; rachis-joint 1/2 the length of the sessile spikelet. Lower glume subcoriaceous,linear-lanceolate, 2-keeled, shortly ciliate along keels, furrowed on the back, as long as the spikelet; upper glume deltoid-lanceolate, l-keeled, keel ciliate, margins membranous, inrolled, minutely fimbriate; lower lemma, if present, lanceolate chartaceous, about 1.5 mm long; upper lemma linear, 1-nerved, with an awn arising from the tip, nearly as long as the lemma; upper palea chartaceous, about 0.5 mm long. Caryopsis about 1.5 mm long; embryo 1/3 the length of the caryopsis.

Rambling annual, rooting at the lower nodes, culms 20-100 cm long. Leaf-blades broadly linear to lanceolate, thin, 1-8 cm long, 2-13 mm wide. Inflorescence composed of 2-10 slender subdigitate racemes, each 2-8 cm long and tending to spread at right angles to the main axis, internodes filiform, glabrous, as long as or longer than the loosely spaced spikelets. Spikelets lanceolate-elliptic, 2.5-5 mm long; lower glume with a broad shallow median groove, glabrous (except for the bearded callus) or finely ciliate near the apex; upper glume weakly keeled or rounded on the back, acute; lower floret represented by a narrowly lanceolate hyaline scale; upper lemma linear, 1.5-2 mm long, hyaline, entire or minutely bidentate, with a capillary awn 6-20 mm long; palea absent or minute; anthers 2, each 0.5-1 mm long.

Annual. Culms rambling, rooting at lower nodes, 20–80 cm long, nodes pubescent. Leaf sheaths glabrous, one margin ciliate; leaf blades narrowly lanceolate, thin, 3–8 × 0.5–1.1 cm, usually glabrous, midvein a white line below middle, apex acute; ligule ca. 0.5 mm. Racemes 2–7, very slender, slightly flexuous, lower becoming divaricate, 4–8 cm; rachis internodes filiform, glabrous, longer than spikelet. Sessile spikelet 3.5–5 mm; callus hairs 1–1.3 mm; lower glume narrowly lanceolate-oblong, back shallowly concave, glabrous or rarely hispidulous near apex, 2–4-veined, apex attenuate, hyaline, sometimes 2-toothed; upper glume weakly keeled or rounded on back, acuminate; lower lemma lanceolate, hyaline, slightly shorter than glumes; upper lemma linear, hyaline, 1.5–3 mm, emarginate; awn very fine, flexuous, 1–2 cm, apex hairlike, tangled; upper palea absent or minute. Anthers 2, 0.5–1 mm. Fl. and fr. Aug–Oct.

Nepal, India, S.E. Asia, China, Korea, Japan.

Widely distributed in India, extending into Southeastern Asia to Japan.

Distribution: Pakistan (Punjab, N.W.F.P. & Kashmir); India to Japan and Australia; tropical Africa.

Anhui, Fujian, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Bhutan, India, Japan, Nepal, Pakistan, Philippines, Vietnam; Africa, Australia].

1800-3200 m

Fl. & Fr. Per.: August-October.

Moist mountainsides, forest undergrowth; ca. 3000 m.

Pollinia nuda Trin., Mem. Acad. St. Petersb. VI. Math. 2: 307. 1823.
Eulalia nuda (Trin.) Kuntze, Rev. Gen. Pl. 2: 775. 1891.
Microstegium mayebaranum Honda, Monogr. 405. 1930.
Pollinia arisanensis Hayata, Icon. Pl. Formos. 7: 74. 1918.
Microstegium arisanense (Hayata) A. Camus, Ann. Soc. Linn. Lyon s. n..68: 201. 1921.

Pollinia nuda Trinius, Mém. Acad. Imp. Sci. St.-Pétersbourg, Sér. 6, Sci. Math. 2: 307. 1833; Eulalia nuda (Trinius) Kuntze; Leptatherum royleanum Nees; Microstegium arisanense (Hayata) A. Camus; Pollinia arisanensis Hayata.