Eriophorum mandshuricum Meinshausen; E. russeolum var. majus Sommier; Scirpus russeolus (Fries) T. Koyama var. major (Sommier) T. Koyama.

Rhizomes creeping. Culms erect, 30-60 cm tall, slender, terete. Basal leaves linear, ca. 1 mm wide, subterete, apex obtuse. Cauline leaves 1 or 2, reduced to bladeless leaf sheaths. Leaf sheaths grayish black with reddish fine transverse veins, cylindric, 6.5-7.5 cm, apically slightly inflated, apex obtuse. Involucral bracts grayish black, glumelike, ovate-lanceolate, 3-9-veined, apex acuminate. Inflorescences terminal with only 1 spikelet. Spikelet oblong-cylindric and 1.5-2.5 cm in flower, obovoid, fairly lax, and 2.5-4 cm in fruit. Glumes brownish gray, ovate-lanceolate, ca. 7 mm, thinly membranous, 1-veined, margin broadly whitish hyaline, apex obtuse. Perianth bristles 10 or more, usually pale reddish brown to reddish, ca. 3 mm. Stamens 3; anthers linear, 2-3 mm. Stigmas 3. Nutlet oblong-obovoid to obovoid, ca. 2.5 mm, compressed 3-sided, margin spinulate, apex beaked. Fl. and fr. Jun-Jul. 2n = 58, 60, 62.

Marshes, moist places; below 100 m. Heilongjiang, Jilin, NE Nei Mongol [Japan, Korea, Mongolia, Russia; N Europe, North America].