| Noun | 1. | ditchmoss - submerged freshwater perennials liliopsid genus, monocot genus - genus of flowering plants having a single cotyledon (embryonic leaf) in the seed family Hydrocharidaceae, family Hydrocharitaceae, frogbit family, frog's-bit family, Hydrocharidaceae, Hydrocharitaceae - simple nearly stemless freshwater aquatic plants; widely distributed waterweed - a weedy aquatic plant of genus Elodea |