Stipitate stereoid basidiocarps have evolved multiple times

Stipitate stereoid fungi are Basidiomycetes with a stipe, a spathulate- to funnel-shaped pileus, a smooth hymenophore, and hyaline, smooth spores. Representatives of the genera Cotylidia, Cymatoderma, Muscinupta, Podoscypha and Stereopsis were subjected to molecular phylogenetic analyses based on nuclear ribosomal large subunit, 5.8S and ITS sequences. For four of the genera the type species was included in analyses. Stereopsis radicans, the type species of Stereopsis, forms a lineage with the corticioid species Clavulicium globosum but could not be placed in any of the presently accepted orders within Agaricomycotina. Stereopsis vitellina falls within the Atheliales, making it the first pileus- and stipe-forming fungus recovered in this order. Cotylidia and Muscinupta again are shown to be members of the Hymenochaetales, whereas Cymatoderma and Podoscypha belong in the Polyporales. Cymatoderma is polyphyletic and Cymatoderma sensu stricto is separated from other stipitate stereoid fungi in the Polyporales, whereas the remaining Cymatoderma species are nested within a well supported clade holding all Podoscypha species but also Abortiporus biennis.