Revising the taxonomic placement of <i>Laetiporus persicinus</i> within the Laetiporaceae

The fungus currently known as <i>Laetiporus persicinus</i> is a recognizable brown-rot decayer that is widespread on oak hosts in the southeastern United States. This species was first described as <i>Polyporus persicinus</i> in 1872 based on collections by Henry W. Ravenel from South Carolina. In this study, we elucidate the phylogenetic relationships of <i>Laetiporus persicinus</i> based on maximum likelihood and Bayesian inference analyses of a four-locus data set (18S, 28S, <i>rpb2</i>, and <i>tef1</i>) from taxa within the Fomitopsidaceae and Laetiporaceae. The internal transcribed spacer (ITS) region was analyzed separately because it was not possible to align this locus across a diverse data set that included taxa from multiple families. Our analysis and previous studies indicate that <i>Laetiporus persicinus</i> does not belong to <i>Laetiporus</i> sensu stricto, and we found a strongly supported relationship between <i>Laetiporus persicinus</i> and the African species <i>Kusaghiporia usambarensis</i>, despite the fact that the 28S phylogeny resolved a different (but unsupported) topology. Here, we propose <i>Kusaghiporia persicinus</i>, comb. nov., based on a combination of morphological and molecular data. <i>Laetiporus persicinus</i> shares many morphological features with <i>K. usambarensis</i> that are missing in other <i>Laetiporus</i> species, including centrally stipitate basidiomata, a brown to pinkish pileus surface, and a pore layer that bruises when touched. However, <i>K. usambarensis</i> and <i>L. persicinus</i> differ in basidiospore size and shape as well as their geographic distributions. We provide a revised taxonomic treatment for this common wood-decay fungus.