wolffia

Century Dictionary and Cyclopedia

1. n. A genus of monocotyledonous plants, of the order Lemnaceæ, distinguished from Lemna, the other genus, by one-celled anthers and by the absence of roots. The 12 species are chiefly tropical, occurring in Europe, India, Africa, and America, and extending north into the United States; they are commonly globose, sometimes conical or flatfish, with a proliferous base, and produce minute flowers from chinks in the surface, each flower consisting of a single stamen or ovary without any spathe or other envelop. They are known, like Lemna, as duckmeat, and are remarkable for their almost microscopic size, being esteemed the smallest of flowering plants.

WordNet 3.0

1. n. minute rootless aquatic herbs having globular fronds floating on or near the water surface and bearing one flower per frond