Columbian watermeal, Wolffia columbiana, is one of three look-alike species of Wolffia in Nebraska. Pinhead sized, they are the world’s tiniest plants to bear flowers. Often massively abundant floating on warm, quiet, unpolluted waters almost anywhere in Nebraska, the plants are seldom noticed. They have no roots, stems, or leaves, but instead are a mass of green cells, and the only clue that they are true flowering plants is their minuscule flowers, which are too small to be seen except under a microscope. The Wolffia are seen here with a larger relative, duckweed (Lemna) on a finger.