Description from Flora of China
Gratiola repens Swartz, Prodr. 14. 1788; Sinobacopa aquatica D. Y. Hong.
Annuals. Stems creeping and rooting at nodes at least basally, branched, 12-20 cm, internodes 3-6 cm, succulent. Leaves sessile, obovate to obovate-lanceolate, 1.2-2.5 X 0.7-1.3 cm, smaller on branches, margin entire; veins 9 or 10, par-allel. Flowers axillary, pendulous. Pedicel 1-2 cm. Bracteoles absent. Sepals (4 or)5, 3-4 mm, margin ciliate, apex obtuse; lower and upper sepals linear-elliptic, 5-veined; lateral 2 sepals linear, 1-veined. Corolla white, almost as long as sepals; lobes obovate, apex rounded; upper lip lobed to middle, lobes narrowly obovate, apex rounded. Stamens equal, ca. 1.2 mm, inserted at throat; filaments as long as anthers; anthers sagittate. Stigma 2-parted; lobes reflexed. Capsule globose, ca. 1.7 mm in diam. Seeds columnar-oblong, ca. 0.5 mm; seed coat reticulate. Fl. Aug-Sep.
Paddy fields; low elevations. Fujian (Fuzhou Shi), Guangdong (Guangzhou Shi), Hainan (Lingshui Xian) [North and South America].