Limnobium spongia

(Bosc) Richard ex Steudel

Nomenclator Botanicus. Editio secunda 2: 45. 1841.

Common names: American frogbit
Basionym: Hydrocharis spongia Bosc Ann. Mus. Natl. Hist. Nat. 9: 396. 1807
Treatment appears in FNA Volume 22.

Herbs, to 50 cm. Roots branched; stolon buds with 10 or more roots. Leaves floating or emersed in dense vegetation and when stranded; blade 1–10 × 0.9–7.8 cm; primary veins forming 30–80° angle with midvein, ascending, aerenchyma extensive, nearly margin to margin, individual aerenchyma space (located ca. 1 mm from either side of midvein) , 0.4–1.6 mm wide, 1 mm from midveinacross its longest axis. Flowers: staminate flowers with 9–12(–18) stamens; pistillate flowers with 3–4 petals; ovary 6–9-carpellate, locules 6–9; styles 2-fid nearly to base; ovules 200. Fruits 4–12 mm diam.

Phenology: Flowering summer–fall.
Habitat: Floating on slow-moving water of streams, bayous, and lakes or stranded along shore
Elevation: 0–100 m


V22 424-distribution-map.jpg

Ala., Ark., Del., Fla., Ga., Ill., Ky., La., Md., Miss., Mo., N.Y., N.C., Okla., S.C., Tenn., Tex., Va.


No specimens have been seen from New Jersey, but although the species is to be expected there.

Limnobium spongia has two leaf forms, often on the same plant. The floating leaves have a thick layer of aerenchyma on the abaxial surface; the emersed leaves lack such tissue. Flowering and fruiting are predominantly on individuals with emersed leaves. Following pollination, the peduncle becomes recurved, forcing the developing fruit below the water surface.

Selected References


Lower Taxa

... more about "Limnobium spongia"
Robert R. Haynes +
(Bosc) Richard ex Steudel +
Hydrocharis spongia +
American frogbit +
Ala. +, Ark. +, Del. +, Fla. +, Ga. +, Ill. +, Ky. +, La. +, Md. +, Miss. +, Mo. +, N.Y. +, N.C. +, Okla. +, S.C. +, Tenn. +, Tex. +  and Va. +
0–100 m +
Floating on slow-moving water of streams, bayous, and lakes or stranded along shore +
Flowering summer–fall. +
Nomenclator Botanicus. Editio secunda +
Illustrated +  and Endemic +
Limnobium spongia +
Limnobium +
species +