(Mart.) Hara, J. Jap. Bot. 28:292.1953
Jussiaea natans H. & B.
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.
Apparently once common at the edge of the lake and no doubt still occurring in marshy areas on the southern and western edges of the island. Apparently flowers and fruits throughout the year.
Southern Mexico to Peru and Paraguay. In Panama, known from tropical moist forest in the Canal Zone, Panama, and Darién.