Aquatic, apparently leafless, ± succulent annual, 6-30 mm tall, main stem a solitary, enlarged, club-shaped internode, terminated by smaller, club-shaped branchlets, often reddish. Leaves fused into a fleshy ring indistinguishable from stem. Flowers few, terminal, star-shaped, petals 1-2 mm long, white or pinkish.
Apparently leafless annual, 0.6-3 cm, with a larger, single-noded, clavate stem terminated by smaller, clavate branches. Leaves fused into a fleshy ring indistinguishable from stems. Flowers terminal, star-shaped, white or pinkish, petals 1-2 mm long, ovules 1(2) per carpel.