ABSTRACT: The structure of the cortex of the sclerotium is indicated as a diagnostic character for the Collybia species with small fruit bodies - those of Collybia sensu stricto, e.g., C. cookei, C. racemose, and C. tuberosa. This feature permits faster and easier identification of these taxa, in both fresh and dry herbarium material.

KEYWORDS: Basidiomycetes, Agaricales, Tricholomataceae, Collybia, sclerotium, sclerotial surface, diagnostic character.

NOMENCLATUAL NOVELTIES: None.