duckweed

名词 duckweed:

1. any small or minute aquatic plant of the family Lemnaceae that float on or near the surface of shallow ponds

duck.weed

n.（名词）
Any of various small, free-floating, stemless aquatic flowering plants of the genusLemna.
浮萍：一种浮萍科 小而无根，自由浮动的水生开花植物