OregonFlora species comparison

up to 15 cm long.

0.8–1.6 mm diameter; greenish brown, formed in the fall and sink to the bottom.

floating on the surface, orbicular to widely elliptic or obovate; (1)2–4 mm long, 1–1.5 times longer than wide, 3 veins;

lower surface flat, usually reddish especially near root attachment;

upper surface green, sometimes with red spots, with a row of 3–7 papillae along a midline ridge, generally in clusters of 2 or 3.