Disentangling the basidiomycete family Agaricaceae

The family Agaricaceae is one of the most diverse and species-rich families within the phylum Basidiomycota with a variety of fruiting body morphologies (agaricoid, secotioid, and gasteroid), ecological roles (e.g., saprotrophs and ant mutualists), and products of economic value (e.g., as food and medicine). The latest classification based on morphology and molecular data recognized around 59 genera within this family. The classification of Agaricaceae has, however, changed through time and is still in continuous review. Here, we used a multilocus approach sequencing the markers ITS, LSU, RPB2, and TEF1 for most of the type species of genera traditionally included in the Agaricaceae using taxa from Tricholomataceae and Lyophyllaceae as outgroups. Based on our taxon-dense phylogenetic analyses, we propose Agaricaceae to be divided into tribes following and expanding on Singer’s (1986) classification: Agariceae, Coprineae, Cystolepioteae, Leucocoprineae, Lepioteae, Lycoperdeae, Macrolepioteae, and Tulostomateae. Furthermore, we conclude that the family Lycoperdaceae should be included within Agaricaceae and that Nidulariaceae should remain a separate family outside Agaricaceae. This is the first study of this family including agaricoid as well as secotioid and gasteroid species representatives, confirming their position within Agaricaceae. Our results further clarify the classification of this important mushroom family supporting previous morphological work as well as novel relationships. Nevertheless, the classification of various species within the genera Agaricus, Leucoagaricus, Leucocoprinus, Macrolepiota, and Morganella remain unresolved, and we suggest further studies may be needed with more data (genome-level phylogenies) as well as relevant species to resolve pending relationships within those particular genera.