Agaricus abruptibulbus Peck Knolliger Egerling, Özlábcsiperke, gumós csiperke. Cap 8–12cm across, convex, often with a slight umbo, whitish bruising yellowish. Stem 80–120 x 10–30mm at the characteristic, abruptly marginate bulb, coloured as cap; ring large, white and pendulous, with cog-wheel ornamentation on lower side. Flesh white, becoming yellowish to brownish when cut. Smell of aniseed. Gills pallid at first then clay brown. Cheilocystidia thin-walled, oval or globose. Spore print brown. Spores elliptic, 6–8 x 4–5µ. Habitat with spruce. Season late summer to late autumn. Occasional. Edible. Distribution, America and Europe. Considered by some American authors to be a form of Agaricus silvicola.