|duckweed (Lemna, Spirodella, and Wolffia spp.)||
duckweed (Lemna, Spirodella , and Wolffia spp.; DUCKWEED FAMILY [Lemnaceae]) Tiny floating perennial plants without leaves, consisting of a globular or flattened thallus with or without roots, and very rarely producing tiny white flowers. Mostly reproduce from vegetative buds. Occur in nutrient-rich lakes and ponds, tending to accumulate on leeward side. Sink and overwinter in bottom mud. 
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