Leaves lanceolate, 2.3--5.6 cm × 3--4 mm, veins 7--9. Scapes 3--21, 6--21 cm, 4--6-ribbed; sheath 2.5--5 cm; receptacle densely pilose or villous; heads ± blackish, 3.5--5 mm in diam.; involucral bracts broadly ovate-orbicular to narrowly lanceolate, 2.5--3 × 1.5--2 mm, papery, glabrous; floral bracts blackish, obovate-oblanceolate, 1.5--1.7 mm, hoary toward apex. Male flowers: sepals 3, blackish, spathelike, flat, ca. 2 mm, abaxially hairy along midvein and toward 3-cleft apex; petals 3, lanceolate, anterior one larger than others, hairy at apex, gland absent; stamens 6, anthers black. Female flowers: sepals 3, blackish, free, ca. 1.7 × 0.5 mm, abaxially hairy along midvein and toward acuminate apex; petals 3, oblanceolate, ca. 1.2 × 0.1 mm, adaxially pilose toward acute to emarginate apex, gland absent; ovary 3-loculed; style 3-cleft. Seeds ellipsoid, 0.3--0.4 mm in diam.; testa transversely elongate reticulate, prickles linear. Fl. and fr. Jul--Oct.

Marshlands, stream banks; 300--1700 m. Guangxi, Guizhou [India, Thailand].