羽毛荸荠 yu mao bi qi

Eleocharis petasata (Maximowicz) G. Zinserling; Scirpus petasatus Maximowicz.

Perennials. Stolons short or absent. Culms grayish green, tufted, 30-60 cm tall, slender, sharply 4-angled, smooth. Leaf sheaths 1 or 2, reddish to purplish, mouth very obliquely truncate. Spikelet brownish at first but becoming pale green, ovoid, narrowly ovoid, or oblong, 8-15 × 3-5 mm, slightly oblique, many flowered, apex acute. Basal 2 glumes empty; basalmost glume amplexicaul for whole spikelet base; fertile glumes pale green medially and rust-colored striate on both sides, tightly spirally imbricate, oblong to elliptic and boat-shaped, 4-6 × 2-2.5 mm, membranous, midvein thin and obscure, margin broadly hyaline, apex obtuse-rounded. Perianth bristles 6, rust-colored, as long as nutlet (including style base), plumose with spreading hairs. Stigmas 3. Nutlet pale olivaceous, turning brownish when mature, shortly stipitate, obovoid to broadly obovoid, ca. 1.5 × 2 mm, obtusely 3-sided, slightly compressed, both surfaces smooth, apex not constricted; persistent style base very inflated, narrowly ovoid, as long and as wide as nutlet or nearly so, laterally compressed, densely mammillate, apex acute to obtuse. Fl. and fr. Jul-Sep.

Shallow water in valleys, grasslands by water, marshy areas; 900-1700 m. Anhui, SE Gansu, W Hebei, Heilongjiang, Henan, Hubei, Jiangsu, Jilin, Liaoning, NE Nei Mongol, S Shaanxi, Shandong, Zhejiang [Japan, Korea, Russia (Far East, Siberia)].