2. Bolboschoenus planiculmis (F. Schmidt) T. V. Egorova in Grubov, Rast. Tsentral. Azii. 3: 20. 1967.
扁秆荆三棱 bian gan jing san leng
Scirpus planiculmis F. Schmidt, Mém. Acad. Imp. Sci. Saint Pétersbourg, Sér. 7, 12(2) [Reis. Amur-Land., Bot.]: 190. 1868.
Rhizomes creeping, terminated in a globose tuber. Culms solitary from a tuber, 60-100 cm tall, usually ± slender, 3-angled, smooth. Leaves basal, shorter to slightly overtopping inflorescence; sheath brownish, 5-16 cm; leaf blade linear, 2-5 mm wide, flat, apex acuminate. Involucral bracts 1-3, leaflike, often surpassing inflorescence, margin scabrous. Inflorescences of 1-6 spikelets, capitate or simple paniculate; rays 1 to few, short, each terminated by 1 to few spikelets. Spikelets rust-colored brown, ovoid to oblong-ovoid, 10-16 × 4-8 mm, many flowered. Glumes brown to dark brown, oblong to elliptic, 6-8 mm, membranous, abaxially sparsely pubescent, 1-veined costa projected beyond apex forming an awn, apex lacerate. Perianth bristles 4-6, 1/2-2/3 as long as nutlet, retrorsely scabrous. Stamens 3; anthers linear, 3-4 mm; connective apex ca. 0.5 mm. Style slender; stigmas 2. Nutlet broadly obovoid to obovoid, 3-3.5 mm. Fl. May-Jan, fr. Jul-Sep. 2n = 50, 52, 56, 108.
Wet places by lakes and riverbanks, swampy areas; near sea level to 2900 m. Anhui, Gansu, Hebei, Heilongjiang, Henan, Hubei, Jiangsu, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Taiwan, Xinjiang, Yunnan, Zhejiang [India, Japan, Kazakhstan, Korea, Kyrgyzstan, Mongolia, Papua New Guinea, Philippines, Russia, Tajikistan; SW Asia, Europe].