密穗莎草 mi sui suo cao

Cyperus vegetus Willdenow.

Perennials, rhizomatous. Culms caespitose, (25-)40-60(-90) cm tall, 3-angled to terete, smooth. Leaf blade (10-)25-50 cm × 5-8(-12) mm, flat or V-shaped. Involucral bracts 4-8, horizontal to ascending at 15-30°. Inflorescence an anthela, flat or sometimes V-shaped, 3-30(-50) cm × 1.5-8(-12) mm; rays (0-)3-10, 2.5-5(-12) cm; raylets usually absent. Globose head of (20-)30-50(-70) spikelets at apex of each ray, (1-)2-4 cm in diam. Spikelets oblong, 0.5-2 cm × 2.2-3 mm, compressed. Glumes (12-)20-30(-50), whitish to golden brown, ovate-deltoid, 2-2.3 × 1-1.4 mm, basally 2-keeled, laterally veinless. Stamen 1; anther 1-1.2 mm. Style 1-1.2 mm; stigmas 3, ca. 0.5 mm. Nutlet black to dark brown, with a ca. 0.1 mm stipe, broadly ellipsoid, 1.2-1.4 mm, 3-sided, puncticulate, apex apiculate with a 0.2-0.3 mm beak. Fl. and fr. Jul-Aug. 2n = 42.

Damp grasslands, shores; below 200 m. Naturalized in N Taiwan [native to North and South America and Pacific islands (Easter Island)].

Cyperus eragrostis is naturalized in S Africa, Australia, and Europe.

This species is reported here for the first time from China, based on two collections: Taiwan: Taibei, Huang Chien-I 1640 (HAST); Yilan, Dongshan Xiang, Liong Wai-Chao 3809 (HAST).