Aquatic. Inflorescence erect, 5-20cm long; Ovary globose, style distinct, stigma lower lip orbicular, reflexed, upper lip narrowly deltoid, both fimbriate. Capsule globose, c. 3 mm long, circumscissile. Seeds lenticular-prismatic, c. 0.6 mm ø, very narrowly winged on the angles.
Asia-Tropical: New Guinea present, Burma present, Circumboreal present, Himalaya present, Mt Hagen area present
Circumboreal, extending southwards into the Himalaya, Burma, and Malesia: New Guinea (Mt Hagen area).
The three Malesian specimens seen are without inflorescences but there can be little doubt that they are the same as the circumboreal plant. The small, almost glabrous, turions distinguish it from all other species in the genus. Like U. australis it is probably distributed by migratory birds.