Russia Flora: An aquatic plant, either attached to the bottom of water bodies or creeping along wet depressions and puddles. Stems up to 50 cm long, sometimes longer, 1-2 mm in diameter, with long internodes and thin adventitious roots emerging from nodes. Leaves on long thin petioles, 3-10 cm long; blade 1-4 cm in diameter, cordate-reniform, with entire or slightly wavy margins. Flowers up to 1 cm in diameter, usually floating or rising above the water surface. Flower stalks 4-8 cm long. Perianth segments elliptical, white. Fruit composed of 20-30 tightly joined carpels; carpels 4-5 mm long, smooth, with straight style about 0.5 mm long. 2n = 32 (Zhukova, Petrovsky, 1975). 

Distribution: Chukotka (west, south), Anadyr, Anadyr-Penzhina, Koryak, Kolyma, Okhotsk, Aldan, Dauria, Kamchatka, Upper Zeya, Lower Zeya, Bureya, Amgun, Ussuri (Figure 3). - In freshwater bodies, more often near shores, in wet depressions, bogs, waterlogged meadows, and old river channels. Flowering period: June-July. - General distribution: Western and Eastern Siberia; Mongolia, Japan-China (PRC, Korean Peninsula), North America (Alaska, western Canada). - Described from Siberia.

Note: Along with the typical (floating) form, var. reptans (V. Vass.) Tolm. occurs in different parts of the range (without strict geographical confinement) in wet depressions, periodically flooded meadows, and shallow puddles, distinguished by creeping nodose stems with shorter internodes. A race of this species with 2n = 16 is reported from Canada (Packer, 1964), while in the Asian part of the range, only the race with 2n = 32 is known.