Molecular confirmation of Leucoagaricus idae-fragum (Agaricales, Agaricaceae), and notes on its morphological variability

Leucoagaricus idae-fragum, a very rare pink-lilac lepiotoid species originally described from France, was synonymised with the North American taxon Lepiota decorata by Vellinga (2006), but 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 sites in Italy, and from the holotype collection. Morphological investigations of all these collections revealed high variability in the shape of the cheilocystidia and spores, and inconsistency of the ammonia reaction, characters which have always been considered to be quite stable within a single species and traditionally used for differentiating 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.