Japan Flora: Fronds submersed, flat, green, 8-10 mm. long, 2-4 mm. wide, narrowly deltoid to ovate-oblong or broadly deltoid-lanceolate, rather obtuse to subacute, minutely serrulate on the upper margin, 3-nerved, truncate or rather sagittate and short-stiped at base, with 1 or few daughter fronds; root single, sometimes wanting. Ponds, ditches, and still waters.
Hokkaido, Honshu, Shikoku. Europe, Asia, Africa, Australia, and N. America.