ABSTRACTA new genus in the Entolomataceae is described from North America. While in many respects it is microscopically similar toRhodocybeMaire,Rhodocybelladiffers markedly fromRhodocybein three important features.Rhodocybellaproduces basidiomes with cupulate pendant pilei which are laterally attached, the hymenophore is smooth or produces a few rudimentary lamellar folds, and the hyphae of the pileipellis form knobby to subdiverticulate projections. These features are not found in members ofRhodocybe. Rhodocybella rhododendrihas only been collected from the surface of the periderm of livingRhododendron maximumL. stems after periods of heavy rainfall.