Description from Flora of China
Herbs scapigerous, aquatic or growing in marshes, rarely on dry ground. Stems very short and disciform, rarely elongate. Leaves radical, linear. Scapes 3--8-ribbed; sheath oblique at mouth. Bracts scalelike. Flowers unisexual, with both sexes in same head, minute. Male flowers: sepals 2 or 3, usually connate into an abaxially split tube, rarely free; petals basally connate and funnelform, large, margin usually ciliate, apex distinctly or indistinctly 2- or 3-lobed, usually bearing a gland; stamens in 2 whorls, adnate to petals; anthers black or rarely yellowish. Female flowers: sepals 2 or 3, free, basally connate, or connate into an adaxial spathe, flat, boatlike, or crested, equal or unequal; petals absent to 3, linear, oblanceolate, or spatulate, margin ciliate, apex often bearing a large gland; ovary 1--3-loculed; style 1--3-branched. Seeds yellowish or brown, 1 per valve; testa usually hexagonally reticulate, prickles small and in rows or absent; embryo minute.
Eriocaulon occurs throughout most of China except for Ningxia, Qinghai, and Xinjiang.
About 400 species: mainly in tropical and subtropical regions, with a concentration in Asia; 35 species (13 endemic) in China.