Japan Flora: Stems 5-10 cm. long, loosely branched, densely leaved, the two lateral foliar blades herbaceous, pale green, spreading, slightly imbricate, soft, elliptic to oblong, 8-15 mm. long, 6-10 mm. wide, flat or very slightly folded, pinnately arranged, rounded at apex, slighdy cordate bristlelike hairs on upper surface, soft-puberulent beneath, the submerged leaf finely dissected and rootlike; sporangia of two kinds, fascicled, globose, pubescent. Sept.-Nov. Ponds and paddy fields in lowlands.
Honshu, Shikoku, Kyushu; common. Europe to India and e. Asia.