Collybia tuberosa (Bull. ex Fr.) Kummer Knolliger Rubling, Lentil Shanklet. Cap 5-l0mm across, convex becoming flat or rarely with an umbo; whitish or very weakly tinted buff; smooth, dry. Gills adnate, close, narrow; whitish. Stem 10-30 x 1mm, often flexuous; whitish; dry, attached to reddish-brown, tuber-like body. Flesh very thin; whitish. Odor not distinctive. Taste not distinctive. Spores ellipsoid, smooth, 4-5.5 x 2-3ì. Deposit white. Habitat numerous on remains of decaying mushrooms. Found widely distributed in North America. Season August-November (over-winters in California) and in Europe. Not edible.