Muhlenbergia japonica Steudel var. ramosa Hackel ex Matsumura, Bot. Mag. (Tokyo) 11: 444. 1897; M. frondosa (Poiret) Fernald subsp. ramosa (Hackel ex Matsumura) T. Koyama & Kawano.

Plants with creeping scaly rhizomes; rhizomes 11–30 × ca. 0.2 cm. Culms usually erect, 30–120 cm tall, 1–2.5 mm thick, with many branches in upper part. Leaf sheaths loosely overlapping, glabrous; leaf blades 5–12 × 0.3–0.6 cm, flat, thinner, scabrid on both surfaces and margins; ligule ca. 0.5 mm, truncate. Panicle 10–18 cm, narrow; branches one or two per node, usually with spikelets to the base. Spikelets narrowly lanceolate, ca. 3 mm, purplish gray-green; glumes 1.5–2.2 mm with lower glume usually shorter than the upper, broadly lanceolate, 1-veined, apex acute to acuminate; lemma 2.5–3.1 mm, lower 1/4 of back pilose; awn 5–10 mm, gray-green or purple, scabrid. Anthers ca. 0.5 mm. Caryopsis ca. 0.5 mm, brown, narrowly oblong. Fl. and fr. Jul–Oct.

Open forest of mountain valleys, moist places on mountain slopes; 100–1300 m. Anhui, Fujian, Guizhou, Hubei, Hunan, Jiangsu, Jiangxi, Shandong, Sichuan, Yunnan, Zhejiang [Japan].