Japan Flora: stems glabrous; leaves sessile, verticillate in 5’s or 6*s, glabrous, pinnately lobed in the upper half, 1-1.5 cm. long, 3-5 mm. wide, gradually narrowed at base; aquatic leaves finely dissected into linear segments; flowers solitary in axils, the pedicels glabrous, deltoid, acute or with an obtuse tip; capsules about 3 mm. across, broadly ellipsoidal; seeds broadly ellipsoidal, about 0.3 mm. long, dark brown. Sept.
Honshu; rare. Northeastern China, Korea, Formosa, China, India, Malaysia, and Australia.