22. Schoenoplectus supinus (Linnaeus) Palla, Bot. Jahrb. Syst. 10: 299. 1888.
仰卧秆水葱 yang wo gan shui cong
Scirpus supinus Linnaeus, Sp. Pl. 1: 49. 1753; Schoenoplectiella supina (Linnaeus) Lye.
Roots fibrous. Culms greenish, tufted, 4-30 cm tall, 1-1.7 mm thick, 3-angled or terete, clothed at base with 2 or 3 leaf sheaths. Leaf sheaths pale green, 2-6 cm, membranous, mouth obliquely truncate and with a mucro; leaf blade present or absent. Involucral bract 1, culmlike, 1.5-12 cm. Inflorescence a pseudolateral head or corymbose with 4 short rays. Spikelets 3-10, narrowly ovoid, ovoid, or oblong, 4-8 × 2-3 mm, subdensely many flowered, apex subacute. Glumes elliptic and boat-shaped, 1.8-2.5 mm, with a prominent green 3-veined keel, margins membranous, apex ± obtuse and shortly mucronate. Perianth bristles absent or rarely rudimentary. Style ca. 1.5 mm; stigmas 3. Nutlet black at maturity, broadly obovoid, 1-1.3 mm, 3-sided, obscurely or distinctly transversely wrinkled, both ends suddenly contracted, apex mucronate. Fl. and fr. Jul-Sep or Nov-Jan.
Wet places, paddy fields, moist meadows along valleys; 600-2300 m. Anhui, Guangdong, Guangxi, Hainan, S Jiangsu, Taiwan, Xinjiang, Yunnan [Afghanistan, India, Indonesia, Kazakhstan, Malaysia, Myanmar, Nepal, Pakistan, Philippines, Russia, Sri Lanka, Thailand, Uzbekistan, Vietnam; Africa, SW Asia, N Australia, Europe, Madagascar, South America].
Schoenoplectus supinus subsp. supinus occurs in N Africa, C and SW Asia, and S Europe.