Annual herb, rarely up to 0.15 m high. Stems erect or decumbent, often with adventitious roots. Leaves fleshy; blade linear to linear-elliptic, 2-6 x 1-2 mm, apex obtuse or acute, flat above, convex below, glabrous, green to brown or deep red. Flowers: solitary, terminal in axil of a leaf; 4-merous; anthers purple; calyx lobes obtuse, ± as long as lobes; corolla cup-shaped, lobes ovate to elliptic, 1-2 mm long, apex obtuse, recurved, white or tinged red; Sep.-Jan.
Annual, succulent herb, branches up to 0.15 m long, erect, decumbent, in mud around standing water, adventitious roots. Leaves linear, 2-4 x 1-2 mm, glabrous, green to red, fleshy. Inflorescence with terminal flowers in axil of leaf-like bracts. Corolla cup-shaped, scarcely fused at base, white tinged red, 1.2-2.0 mm long, obtuse, recurved from middle; lobes ovate to elliptic, 1.2-2.0 mm long. Flowering time Sept.-Jan.
Delicate, reddish, annual, 20-150 mm tall. Leaves linear, flat above and convex below, 2-4 x 1-2 mm, smooth. Flowers 1(-3) per leaf axil, mostly near branch tips, ± cup-shaped, petals 1-2 mm long, white.
Like C. natans but usually more freely branching and ovules (2-)4-8 per carpel.