frog's-bit

[ frogz-bit, frawgz- ]
/ ˈfrɒgzˌbɪt, ˈfrɔgz- /

noun

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

Origin of frog's-bit

First recorded in 1570–80