Abstract
Leucoagaricus idae-fragum, a nice and very rare pink-lilac lepiotoid species originally described from France, was put into synonymy with the North American taxon Lepiota decorata by Vellinga (2006), only on a morphological basis. In this paper, the independent position of L. idae-fragum from L. decorata is pointed out, based upon the phylogenetic analysis of the nrITS sequences obtained from recently collected specimens of L. idae-fragum from three Italian areas, and from the holotype collection. Morphological investigations of all these collections revealed high variability in shape of the cheilocystidia, spores, inconstant ammonia reaction, characters which have always been considered to be quite stable within a single species and traditionally used for discriminating among species in Leucoagaricus. Full descriptions, with illustrations of fresh basidiomes and of the main macro- and micromorphological features are provided together with a comparison with allied species.