Heteranthera oblongifolia Mart. ex Schult. & Schult. fil.

Heteranthera oblongifolia Mart.; R. & S. Syst. Veg. 7: 1148
1830.
Heteranthera rotiindifolia Griseb. Cat. PI. Cub. 252. 1866.
Heteranthera hydrocleifolia Griseb. Cat. PL Cub. 253. 1866.
Heteranthera limosa var. oblongifolia Solms, in DC. Monog. Phan. 4: 519. 1883.
Plant floating or rooting in mud; stem elongate, branching; leaves erect, the petioles up to 2 dm. long, the blades oblong-elliptic to ovate-cordate, obtuse, 2-5 cm. long; lower spathebract leaf-like, the upper one broadly ovate, sharply curved above, 1.5-3 cm. long, its tip abruptly and minutely caudate ; inflorescence 2-flowered, the lower flower sessile, the upper one pedunculate or absent; perianth-tube whitish, 1-1.5 cm. long, the limb about 2 cm. across, purple, whitish below, the three outer lobes oblanceolate, the three inner obovate; stamens unequal, the filaments pubescent, dilated downward, the larger one 6 mm. long, the smaller ones about 3 mm. long, the anthers linear; style about as long as the small stamens, the stigma three-parted, papillose; capsule 9-15 mm. long, oblong-ellipsoid; seeds narrowly ellipsoid, yellow-brown, 0.4-0.5 mm. long, 0.3 mm. wide, with 10 membranous wings.
Type locality: Sao Francisco River, Province Bahia, Brazil. Distribution: Cuba; also in South America.