Lemna turionifera Landolt

Roots shorter than 15 cm, tip mostly rounded; sheath not winged. Stipes white, small, often decaying. Fronds floating, 1 or 2--few, coherent in groups, obovate, scarcely gibbous, flat, 1--4 mm, 1--1.5 times as long as wide, margins entire; veins 3, greatest distance between lateral veins near or distal to above middle; papillae distinct on midline of upper surface (apical papilla scarcely larger than others); lower surface often red (more intensely so than on upper), coloring beginning at attachment point of root, upper surface (especially near apex) sometimes with red spots; air spaces to 0.3 mm; turions sometimes present, rootless, olive to brown, 0.8--1.6 mm diam., sinking to bottom. Flowers: ovaries 1-ovulate, utricular scale with narrow opening at apex. Fruits 0.5--0.6 mm, not winged. Seeds with 30--60 indistinct ribs, staying within fruit wall after ripening. 2n = 40, 42 (G), 50, 80.