Heteranthera reniformis

Plants annual or facultatively perennial. Vegetative stems submersed with elongate internodes, or emersed and procumbent. Flowering-stems 1–9 cm, distal internode 0.5–4 cm. Sessile leaves forming basal rosette, blade linear to oblanceolate, thin, 2.4–3.7 cm × 3–8 mm. Petiolate leaves floating or emersed; stipule 1–5 cm; petiole 2–13 cm; blade reniform, 1–4 × 1–5 cm, length equal to or less than width, apex obtuse. Inflorescences spicate, 2–8-flowered, elongating in 1 day, usually shorter than spathes, terminal flower sometimes extending beyond spathe apex; spathes 0.8–5.5 cm, glabrous; peduncle 0.5–4.2 cm, glabrous. Flowers opening ca. 3 hours after sunrise, wilting by early afternoon; perianth white, salverform, tube 5–10 mm, limbs zygomorphic, lobes narrowly elliptic, 3–6.5 mm, distal central lobe with yellow or green region at base, sometimes with distal brown spot; stamens unequal, lateral stamens 0.9–2.2 mm, filaments linear, pubescent with white multicellular hairs toward apex; central stamen 2.2–4.7 mm, filament sparsely pubescent with multicellular hairs; style pubescent with multicellular hairs. Seeds 8–14-winged, 0.5–0.9 × 0.3–0.5 mm. 2n = 48.

Phenology: Flowering Jun–Oct.
Habitat: Roadside ditches, edges of streams and ponds, freshwater tidal mudflats
Elevation: 0–2600 m

Ala., Conn., Del., Fla., Ga., Ill., Ind., Ky., La., Md., Miss., Mo., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Tex., Va., W.Va., Mexico, throughout Central America, scattered in South America (Argentina), scattered in South America (Brazil), scattered in South America (Paraguay), naturalized in Italy

Discussion

Selected References

None.

Lower Taxa