5. Eriophorum vaginatum Linnaeus, Sp. Pl. 1: 52. 1753.
白毛羊胡子草 bai mao yang hu zi cao
Eriophorum fauriei E. G. Camus; E. scabridum Ohwi; E. spissum Fernald; Scirpus fauriei (E. G. Camus) T. Koyama.
Rhizomes short. Culms densely tufted, 15-80 cm tall, obtusely 3-angled, smooth but sometimes scabrous below inflorescence, clothed at base with brown leaf sheaths disintegrating into fibers. Basal leaves linear, shorter than culm; leaf blade ca. 1 mm wide, 3-angled, scabrous, apically narrowly tapering, apex obtuse to acute. Cauline leaves 1 or 2, often black, reduced to a bladeless sheath, 3-6 cm with apical one inflated, membranous, with finely transverse veins. Involucral bracts grayish black, glumelike, ovate-lanceolate, membranous, apex acuminate. Inflorescences terminal with only 1 spikelet, 1-3 cm, many flowered, with ca. 10 sterile basal glumes. Spikelet erect, grayish brown, obovoid-globose and ca. 1.5 cm in flower, subglobose and 2.5-3.5 × 2.5-3.5 cm in fruit. Glumes ovate-lanceolate to deltoid-lanceolate, thinly membranous, 1-veined, margin gray to dark gray with pale hyaline edge, apex acuminate. Perianth bristles 10 or more, white, 1.5-2.5 cm. Stamens 3; anthers linear, 2-2.5 mm. Stigmas 3. Nutlet brown, obovoid, 2-2.2[-3] × ca. 1 mm, compressed 3-sided, minutely apiculate, smooth. Fl. and fr. Jun-Sep. 2n = 26, 58, 60, 61, 83.
Swamps, moist places; 1700-1800 m. Heilongjiang, Jilin, N Liaoning, NE Nei Mongol [Japan, Kazakhstan, Korea, Mongolia, Russia; SW Asia, Europe, North America].