Description from
Flora of China
Panicum japonicum Steudel, Flora 29: 18. 1846; Oplis-menus japonicus (Steudel) Honda.
Leaf sheaths glabrous; leaf blades broadly lanceolate or narrowly ovate-elliptic, 5–15 × 1.2–3 cm, glabrous or scabrous. Inflorescence axis up to 15 cm, glabrous. Fl. and fr. Aug–Nov.
Roadsides, moist grasslands. Anhui, Fujian, Guangdong, Guangxi, Hebei, Jiangsu, Jiangxi, Shaanxi, Shandong, Sichuan, Yunnan, Zhejiang [Japan].
