the common botanical name for species of Lemna which form a green coating on fresh-water ponds and ditches. The plants are of extremely simple structure and are the smallest and least differentiated of flowering plants. They consist of a so-called "frond" - a flattened green more or less oval structure which emits branches similar to itself from lateral pockets at or near the base. From the under surface a root with a well-developed sheath grows downwards into the water. The flowers, which are rarely found in Britain, are 2 Probably from "cuck," to void excrement; but variously connected with Fr. coquin, rascal.
developed in one of the lateral pockets. The inflorescence is a very simple one, consisting of one or two male flowers each comprising a single stamen, and a female flower comprising a flask-shaped pistil. The order Lemnaceae to which they belong 1, Lemna minor (Lesser Duckstamen, and a female flower, weed) nat. size. the whole enclosed in a 2, Plant in flower. sheath.
3, Inflorescence containing two 4, Wolffia arrhiza. male flowers each of one (2, 3, 4 enlarged.) is regarded as representing a very reduced type nearly allied to the Aroids. It is represented in Britain by four species of Lemna, and a still smaller and simpler plant, Wolfa, in which the fronds are only one-twentieth of an inch long and have no roots.