frog-bit

noun

1. an aquatic, floating plant, Hydrocharis morsus-ranae, of Eurasia, having thick, roundish, spongy leaves.
2. an aquatic, floating plant, Limnobium spongia, of tropical America, having reddish-brown spotted, oblong, heart-shaped, or ovate leaves.

noun

1. a floating aquatic Eurasian plant, Hydrocharis morsus-ranae, with heart-shaped leaves and white flowers: family Hydrocharitaceae