断节莎 duan jie suo

Cyperus conglobatus Link; C. ferax Richard; C. ferax var. conglobatus (Link) Kükenthal; Mariscus ferax (Richard) C. B. Clarke; Torulinium confertum Desvaux ex Hamilton; T. ferax (Richard) Hamilton ["feroci"]; T. odoratum (Linnaeus) S. S. Hooper.

Annuals or short-lived perennials. Rhizomes short, with fibrous roots. Culms 30-120 cm tall, stout, 3-angled, ± longitudinally sulcate, smooth, basally with leaves, base swollen into tuber. Leaves shorter than culm; sheath purplish brown, long; leaf blade 4-10 mm wide, flat, slightly stiff. Involucral bracts 6-8, obliquely spreading, usually longer than inflorescence. Inflorescence a compound or decompound anthela; rays 5-12, mostly to 20 cm, slightly stiff, each with several raylets; raylets 0-2 cm. Spikes oblong-cylindric, 2-3 × ca. 1.5 cm, with many spikelets. Spikelets slightly laxly arranged, spreading to downward reflexed, linear-cylindric, 0.8-2.5 cm × ca. 1 mm, 10-25-flowered; rachilla with several to 10 or more articulations, wings broadly elliptic with a revolute margin, corky, and yellowish in maturity. Glumes yellowish brown, straw-colored, or slightly reddish on both surfaces but middle abaxially green, slightly lax, ovate-elliptic, 2-3.5 mm, concave, shiny, 7-9-veined, abaxially broadly rounded (not keeled), apex obtuse. Stamens 3; anthers broadly linear. Style of medium length; stigmas 3. Nutlet at first red but black when mature, oblong to obovoid-oblong, ca. 2/3 as long as subtending glume, slightly curved, 3-sided, included by wing of rachilla but apical part exserted. Fl. and fr. Aug-Oct(-Mar).

Riverbanks, streambeds, paddy field margins; near sea level to 700 m. Shandong, Taiwan, Zhejiang [Japan, Korea, Malaysia, Myanmar, Papua New Guinea, Philippines, Thailand, Vietnam; tropical Africa, E Australia, Central, North, and South America, Madagascar, Pacific islands].