Duckweed

Duckweed
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Liliopsida Order: Arales Family: Lemnaceae
Genera
Spirodela Lemna Wolffia Pseudowolffia Wolffiella Wolffiopsis

Duckweed, also known as water lentil, is the smallest flowering plant in the world. The plant consists of a short stem floating vertically in the water, roots in Spirodela and Lemna, and occasionally a flower consisting of two stamens and a pistil (some call it an inflorescence consisting of three unisexual flowers). The fruit is a utricle, a sac containing air and a seed designed to float; that of Wolffia is the smallest in the world, 0.3 mm long. Reproduction is usually by budding (as in yeast; in flowering plants, such structures are usually called runners).

The family contains four to six genera (depending on the taxonomist) and is believed to be descended from Araceae.