Aristida formosana Honda.

Perennial. Culms densely tufted, erect, wiry, 30–60 cm tall, unbranched. Leaf sheaths smooth, longer than internodes, bearded at mouth; leaf blades involute, filiform, curling when dry, 10–20 cm, abaxial surface smooth, adaxial surface pubescent; ligule ca. 0.2 mm. Panicle ovate in outline, open, 1/2 length of plant or more, 20–30 cm; branches 3–15 cm, divaricate, solitary or in small widely spaced groups along central axis, bearded in axils, strongly scabrid, lower part naked, spikelets clustered distally. Spikelets gray-green or purple; glumes unequal with lower longer, linear-lanceolate, 1–3-veined, acuminate-mucronate, lower glume 8–14 mm, scabrid on vein, upper glume 1/2–2/3 length of lower, smooth; callus ca. 0.5 mm; lemma 5–8 mm, terete, smooth; awn branches arising directly from lemma apex, central branch 1–1.5 cm, laterals slightly shorter or subequal to central branch. Anthers 1–2 mm. Fl. and fr. Apr–Dec.

This is a species of local distribution, easily distinguished by its large, open, scabrid panicle and spikelets with inverted glumes (lower glume longer).

Grassy hill slopes. Fujian, Guangdong, Guangxi, Hainan, Taiwan [Cambodia, Indonesia (Celebes), Philippines, Thailand, Vietnam].