Plants annual, glabrous. Stems erect, 10--30(--40) cm, terete or obscurely angular. Basal leaves obovate to oblong-ovate, 1.2--6.5 X 0.7--3 cm, tapering to base forming a short winged petiole, margin entire, apex rounded to obtuse. Stem leaves smaller, short petiolate or sessile, apex obtuse to apiculate. Racemes loose, usually 8--20 cm, 10--20-flowered. Pedicel 6--12 mm; bracts lanceolate, ca. 1 mm, adnate to middle of pedicel. Calyx campanulate, ca. 1 mm, enlarging to 2--2.5 mm in fruit, parted to 1/3; lobes triangular. Corolla white, 2--3 mm in diam.; tube nearly as long as calyx; lobes ovate, apex obtuse. Capsule 2--3 mm in diam. 2n = 24, 26.

River banks, streamsides, areas near water; 100--1300 m. Guangdong, Guangxi, Guizhou, Hunan, Yunnan [Cosmopolitan].