Gaertnera pangati Retzius; Pongatium indicum Lamarck, nom. illeg. superfl.; P. spongiosum Blanco; P. zeylanicum (Gaertner) Kuntze; Rapinia herbacea Loureiro; Sphenoclea dalzielii N. E. Brown; S. pongatium Candolle, nom. illeg. superfl.

Plants glabrous throughout. Stems erect, usually branched, 20-70 cm tall, to 1 cm in diam. Leaves petiolate; petiole to 1 cm; leaf blade abaxially gray or green, adaxially green, long elliptic, elliptic-lanceolate, or ovate-lanceolate, 2-9 × 0.5-2 cm, margin entire. Spikes 1-4 cm; bracts ovate, apex acuminate; bracteoles broadly linear. Flowers less than 2 mm. Calyx lobes ovate-orbicular. Corolla white, ca. 1.5 mm, shallowly lobed; lobes patent. Capsule 2-4 mm in diam. Seeds brown-yellow, ca. 0.5 mm. Fl. and fr. all year.

Paddy fields, wet places. Fujian, Guangdong, Guangxi, Hainan, Jiangxi, Taiwan, S Yunnan (Xishuangbanna) [Bangladesh, India, Indonesia, Malaysia, Myanmar, Nepal, Pakistan, Philippines, Sri Lanka, Thailand, Vietnam; NE and tropical Africa, SW Asia, Madagascar; introduced in New World tropics].