Annual, with decumbent branches, 20-80 mm tall, often rooting at nodes. Leaves sessile, lanceolate to narrowly elliptic, ± terete, 6-12 x 4-6 mm, with blister-like papillae. Flowers in tight clusters ± along length of stems, ± cup-shaped, petals ± 1 mm long, white, turning brown.
Sprawling annual with stems often rooting at nodes, to 8 cm long. Leaves opposite, semiterete-lanceolate, papillate. Flowers in sessile or subsessile, axillary cymes, cup-shaped, white, perianth ± 1 mm long.