Two new species of Collybiopsis (Agaricales, Omphalotaceae) from Eastern North America

Two small gymnopoid fungi from the southern Appalachian Mountains and Massachusetts, Collybiopsis complicata sp. nov. and C. prolapsis sp. nov., are identified and described. A new generic nrITS-LSU phylogeny of Collybiopsis places C. complicata and C. prolapsis in a small clade together with C. minor, and an unknown taxon from Arkansas. This clade adds to the growing circumscription of Collybiopsis (= Marasmiellus).