What is the world's smallest flowering plant?

Wolffia is the world’s smallest flowering plant. This genus of rootless aquatic plants consists of tiny green fronds that float on calm freshwater, often resembling grains of cornmeal on the surface.

Individual Wolffia plants are generally less than a millimeter across and have no roots, stems, or conventional leaves. Their flowers are extraordinarily difficult to see: each develops inside a small cavity on the upper surface of the frond and contains a single stamen and pistil.

The answer is commonly given as Wolffia, although particular species have competed for the exact size record. Wolffia globosa, Wolffia australiana, and Wolffia angusta have all been described in record claims, depending on whether researchers measure the plant body, flower, or fruit.

Despite its tiny size, Wolffia grows rapidly, mainly by producing daughter fronds through vegetative reproduction. Some species are also eaten as vegetables in Southeast Asia, where they are known as watermeal or rootless duckweed.