风车草 feng che cao

Cyperus alternifolius Linnaeus subsp. flabelliformis Kükenthal; C. flabelliformis Rottbøll, nom. illeg. superfl.

Perennials. Roots ± thick, fibrous. Rhizomes short, thick. Culms 30-150 cm tall, slightly stout, obtusely 3-angled, base with bladeless sheaths, apically scabrid. Basal leaf sheaths yellowish brown and cataphylloid; apical leaf sheaths pale green and mostly to 20 cm. Involucral bracts 14-24, leaflike, ca. 2 × as long as inflorescence, subequal in length, to 30 cm, 0.5-17 mm wide, margin scabridulous, basally ± horizontal, apically flexuose and ± drooping. Inflorescence a decompound anthela; rays numerous, 3-10 cm, each with 4-10 raylets; raylets 1-1.5 cm, each with 3-9 spikelets. Spikelets clustered at apex of raylets, narrowly ovoid or oblong, 3-12 × 1.5-3 mm, flattened, radially spreading, 8-36-flowered; rachilla straight, wingless. Glumes densely imbricate, ovate, ca. 2 mm, membranous, rusty brown punctate, 3-5-veined, apex acute. Stamens 3; anthers linear, ca. 1 mm, apex setose. Style ca. 1 mm; stigmas 3, ca. 1 mm. Nutlet brown at maturity, not stipitate, broadly ellipsoid, 0.5-0.6 mm, 1/4-1/3 as long as subtending glume, 3-sided, apex not apiculate. Fl. and fr. May-Dec. 2n = 32.

Cultivated as an ornamental in China, sometimes escaped and naturalized along streams and in wet thickets and disturbed areas; below 400 m. Guangdong, Hunan, Taiwan [native to E Africa and SW Asia (Arabian Peninsula)].

Cyperus involucratus is widely cultivated as an ornamental and sometimes naturalized in tropical and subtropical areas worldwide.