Culm geniculate, about 2 mm in diameter, hard. Blade 7-8 cm long by 10 mm wide, hirsute on both surfaces; ligule rounded at the upper part, about 1 mm long, hispid on the back; sheath margins and sheath-mouth densely ciliate. Inflorescence of 3 racemes subdigitately arranged. Spikelets paired, monomorphic; the upper pedicellate, the pedicels nearly as long as the spikelet; the lower sessile 4.5-5 mm long; rachis and pedicel slender, ciliate on margins. Glumes subcoriaceous, as long as the spikelet, the lower linear-lanceolate, 2-keeled, shortly ciliate on keels, the upper deltoid, 1-keeled, acute, upper fioret minute, about 1-1.5 mm long; lemma linear, chartaceous, about 1 mm long, with an awn of about 3.5 mm long, arising from the tip of the lemma; palea membranous, lanceolate about 1.5 mm long. Caryopsis cylindrical, about 1.5 mm long; embryo 1/2 the length of the caryopsis.
CHIAYI: Alishan, Sasaki s. n. Dec. 4, 1933, Kao 4890.
Distributed in Japan.
This species is very close to Microstegium vimineum, but the plant body and spikelets are much larger, it may be an extreme form of the latter species.