7. Schoenoplectus mucronatus (Linnaeus) Palla subsp. robustus (Miquel) T. Koyama, Fl. Taiwan. 5: 214. 1978.
水毛花 shui mao hua
Scirpus mucronatus Linnaeus var. robustus Miquel, Ann. Mus. Bot. Lugduno-Batavi 2: 143. 1865; Schoenoplectus mucronatus var. robustus (Miquel) T. Koyama; S. triangulatus (Roxburgh) Soják; Scirpus acutus J. Presl & C. Presl (1828), not Muhlenberg ex Bigelow (1814); S. mucronatus subsp. robustus (Miquel) T. Koyama; S. mucronatus var. subleiocarpus Franchet & Savatier; S. preslii A. Dietrich; S. triangulatus Roxburgh; S. triangulatus var. sanguineus Tang & F. T. Wang; S. triangulatus var. trialatus Tang & F. T. Wang; S. triangulatus var. tripteris Tang & F. T. Wang.
Rhizomes short. Culms deep green, slightly densely tufted, 45-130 cm tall, 5-11 mm thick, sharply 3-angled with shallowly concave sides, clothed at base with 2-4 leaf sheaths. Leaf sheaths brown, 7-25 cm, membranous to herbaceous, obliquely truncate at mouth. Involucral bract 1, culmlike, upright or obliquely bent, 2-10 cm. Inflorescence a pseudolateral hemispheric head, with (3-)5-20 spikelets. Spikelets brownish greenish, ovoid, oblong-ovoid, or narrowly ovoid, 10-20 × 4-6 mm, terete, densely many flowered, apex subacute. Glumes pale green and brownish tinged usually with reddish brown, broadly obovate, ovate, or broadly ovate, 3.8-5 × 2.5-3 mm, very concave, papery, margin apically minutely ciliolate, apex with a green 1-3-veined costa excurrent into a mucro. Perianth bristles 6, 1.5-2 × as long as nutlet, retrorsely scabrous. Stamens 3; anthers linear, ca. 2.5 mm; connective apex slightly prominent beyond anthers. Style ca. 4 mm; stigmas 3. Nutlet blackish brown at maturity, obovoid to broadly obovoid, 2-2.5 × 1.5-2 mm, compressed 3-sided, conspicuously or inconspicuously transversely wrinkled, ± shiny, base contracted to cuneate, apex rounded to mucronate. Fl. and fr. May-Nov. 2n = 44.
Pond and lake margins, swamps, grasslands in streamsides, paddy fields; 100-2700 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, SE Xizang, Yunnan, Zhejiang [India, Indonesia, Japan, Korea, Malaysia, Sri Lanka; Africa, S Europe, Madagascar].
Only specimens of Schoenoplectus mucronatus subsp. robustus, as interpreted here, have been seen from China by the present authors. If recognized at specific rank, this taxon would be correctly named S. triangulatus. Schoenoplectus mucronatus subsp. mucronatus occurs in Europe and is naturalized in North America.