生活型

herb

形態特徵

• Annual or perennial with very short rhizome;culms densely tufted, 15-70 cm by 1.2-2.5 mm thick, acutely pentagonous, scabird below, clothed at base with 2-4 bladeless sheaths.
• Lower leaves at culmbase bladeless, upper ones as well as those forming sterile shoots bladed; blades linear, to 30 cm by 2-3 mm, acute to acuminate, flattish plicate, scabrid on rib-like angles in upper part; sheaths cylindrical, 3-15 cm long, straw-colored to rusty-brown, obliquely truncate at orifice; ligule absent.
• Inflorescence compound to decompound, loose, 4-10 cm by 3-7 cm; involucre bracts 3-5, setaceous, much shorter than primary branches; primary branches 3-5, patent, 1-5 cm long, scabrous; secondary corymbs subdense. Spikelets many per inflorescence, solitary, ovoidal, 2-5 mm by 1.2-1.7 mm, obutse to acute, rusty-brown or slightly yellowish brown, densely many-flowered.
• Glumes many per spikelet, spiral, ovate, 1.7-2 mm long, rounded or mucronate, membranaceous, yellowish or rusty-brown, margins hyaline pale-brownish, keel 3-nerved, with brown streak. Stamens 1-2; anthers 0.5 mm long. Style triquetrous, glabrous or ciliate above, somewhat dilated at base; stigmas 3. Achenes broadly obovate, trigonous, 0.4-1 mm by 0.3-0.5 mm, cream-yellow, finely cancellated with rows of transversely oblong cells, usually verruculose.

分布

• 台灣 : rice fields and marshy places.
• 世界 : In tropical regions throughout Old World.

引證標本

TAINAN: Nanbuh, Wang 10032.

參考文獻

• KOYAMA, Tetsuo, KUOH, Chang-Sheng & LEONG, Wai-Chao, Flora of Taiwan, second edition 5: 272. 2000.  (Fl. Taiwan 2nd edit.)