A new clitocyboid genus Spodocybe and a new subfamily Cuphophylloideae in the family Hygrophoraceae (Agaricales)

Phylogenetically, the genera Cuphophyllus, Ampulloclitocybe and Cantharocybe are treated as basal in the family Hygrophoraceae, despite weak support. However, the exact phylogenetic positions of the three genera have remained unresolved, and taxa related to these genera are poorly known. In this study, a new clitocyboid genus Spodocybe was proposed based on multigenic phylogenetic inference datasets and morphological evidence. The analyses of ITS as well as two combined datasets ITS-nrLSU-rpb2 and ITS-nrLSU-rpb1-rpb2-tef1-α-atp6 supported that (1) Spodocybe formed a well-supported monophyletic clade; and (2) sisters Spodocybe and Ampulloclitocybe, along with Cantharocybe and Cuphophyllus also formed a monophyletic lineage, as sister to the rest of the Hygrophoraceae. Meanwhile, two new species, namely S. rugosiceps and S. bispora, from southwestern China, were documented and illustrated. These results support the new proposed genus Spodocybe, and that Spodocybe, Ampulloclitocybe, Cantharocybe and Cuphophyllus should be retained in the Hygrophoraceae as a new subfamily Cuphophylloideae.