Galerina Earle: A polyphyletic genus in the consortium of dark-spored agarics

Abstract

The basidiomycete genus Galerina Earle accommodates more than 300 small brown-spored agarics worldwide, predominantly described from the Northern hemisphere. The delimitation of species and infrageneric units hitherto has been based on morphological and, to some extent, ecological characters. In this study we have analyzed nuclear ribosomal LSU and ITS sequences to reveal infrageneric phylogeny and the phylogenetic placement of Galerina among the dark-spored agarics. Sequences from 36 northern hemisphere Galerina species and 19 other dark-spored taxa were analyzed, some of them obtained from EMBL/GenBank. Our results, received from Bayesian and distance methods, strongly suggest that Galerina is a polyphyletic genus. The LSU analysis shows that Galerina is composed of three or four separate monophyletic main groups. In addition, a few species cluster together with other dark-spored agarics. The same groups are recognized in the ITS tree and they correspond roughly to previously recognized subgenera or sections in Galerina. With high support our LSU analysis suggests that Gymnopilus is a monophyletic genus and that Gymnopilus and one of the Galerina lineages (“mycenopsis”) are sister groups. The analyses further indicate that the Galerina lineages, as well as the genus Gymnopilus, could be referred to a strongly emendated family Strophariaceae, which corresponds largely to the family as circumscribed by Kühner (1980). Our results affirm that morphological characters often are highly homoplastic in the agarics. At the present stage formal taxonomic consequences or nomenclatural changes are not proposed.