Aquatic herb, floating on water or prostrate on mud, +/- glabrous; stem conspicuously rooting at nodes, seldom branching. Petioles 1-3 cm long; blades obovate to suborbicular, blunt at apex, abruptly narrowed to petiole, 2-7 cm long, 1.5-4.5 cm wide; lateral veins conspicuous, with a loop-connecting vein. Flowers solitary in axils, usually 5-parted; sepals lanceolate-ovate, ca 5 mm long; petals white with basal yellow spot, oblong-obovate, 8-14 mm long, shortly clawed; stamens 10, unequal, 3-5 mm long; anthers 1-2 mm long; style white, 4-7 mm long; stigma green, slightly lobed, ca 1.5 mm wide. Capsules subcylindrical, 2-3 cm long, ca 3 mm thick; endocarp hard, shining, ca 1.5 mm long; seeds contained in and adnate to the endocarp, uniseriate in each locule. Shattuck 1132.