Gills free from stipe, tan maturing to dark brown. Odor strongly phenolic. Cap convex when young, expanding to nearly flat at maturity. Cap pale with brown fibrils, bruising bright yellow at the margin. Rapid, bright staining and strongly phenolic odor distinguish this from A. californicus, according to Desjardin 2015. Found under redwood in an irrigated landscaped area (Stanford's California Native Plant Garden, near Cantor Arts Center).