丝叶谷精草 si ye gu jing cao

Plants mostly submerged. Stems ca. 25 cm. Leaves filiform, 3--4 cm × ca. 0.2 mm, 1-veined. Scapes 5--15, to 11 cm, 6-ribbed; sheath 2--2.5 cm; receptacle subglabrous or villous; heads dusky, subglobose, ca. 2.5 × 3 mm; involucral bracts reflexed, straw-colored, ovate, ca. 1 mm, membranous, glabrous; floral bracts orbicular to oblanceolate, abaxially white clavate hairy toward apex or glabrous. Male flowers: sepals spathelike, abaxially shortly hairy toward (2 or)3-lobed apex, lobes truncate at apex; petals 3, elliptic to subulate, small, anterior one slightly larger than others, adaxially white clavate hairy, abaxially white clavate hairy toward apex, gland black, sometimes absent; anthers black. Female flowers: sepals 3, free, boatlike to obovate, abaxially white clavate hairy toward margin; petals 3, free, oblanceolate-linear, unequal, membranous, gland black, sometimes absent; ovary 3-loculed; style 3-cleft. Seeds narrowly ovoid, 0.3--0.4 mm; testa hexagonally reticulate, prickles 1 or 2 per cell, linear, slimy coated. Fl. and fr. Aug--Oct.

Ponds, swamps; near sea level to 1300 m. Guangdong, Guangxi, Sichuan, Yunnan [Bangladesh, Cambodia, India, Indonesia, Japan, Laos, Myanmar, Sri Lanka, Thailand, Vietnam; N Australia].