Small subsucculent annual herbs. Land forms glab. or with a few scattered hairs; stems and branches slender, rooting at nodes, forming loose or rather dense patches up to 15 cm. across. Lvs very shortly petioled; lamina (1)-2-4-(5) × 0·5-3 mm., oblong to ovate to elliptic, obtuse; margins sparingly glandular, entire to sinuate or minutely serrulate; stipules minute, fugaceous. Fls minute, solitary, sessile; sepals 3, petals 3 > sepals or 0; stamens 6-3. Capsules globose-depressed, seeds up to 10, ridged, transversely wrinkled. Submerged forms rooted in mud up to 30 cm. below water-surface; stems and branches erect, reaching water-surface, internodes elongate; lvs up to 12 × 6 mm. or more, entire to shallowly sinuate.

2n = 36