| Noun | 1. | Lemnaceae - family of small free-floating thalloid plants liliopsid family, monocot family - family of flowering plants having a single cotyledon (embryonic leaf) in the seed Arales, order Arales - Araceae; Lemnaceae duckweed - any small or minute aquatic plant of the family Lemnaceae that float on or near the surface of shallow ponds genus Lemna, Lemna - minute aquatic herbs floating on or below the water surface of still water consisting of a leaflike frond or plant body and single root genus Spirodela, Spirodela - minute aquatic herbs floating on the water surface consisting of a shiny leaflike frond and 2-21 roots genus Wolffia, Wolffia - minute rootless aquatic herbs having globular fronds floating on or near the water surface and bearing one flower per frond genus Wolffiella, Wolffiella - minute rootless aquatic herbs having flat fronds floating on or below the water surface and bearing 1-2 flowers per frond; America and Africa |