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.目前被称为桃色层孔菌（*Laetiporus persicinus*）的真菌是一种特征鲜明的褐腐分解菌，广泛分布于美国东南部的栎属寄主上。该物种最初于1872年以Henry W. Ravenel在南卡罗来纳州采集的标本为模式标本，被首次描述为桃色多孔菌（*Polyporus persicinus*）。本研究基于对白肉迷孔菌科（Fomitopsidaceae）和层孔菌科（Laetiporaceae）内类群的四位点数据集（18S、28S、*rpb2*和*tef1*）开展最大似然法与贝叶斯推断分析，阐明了桃色层孔菌的系统发育关系。由于无法在涵盖多科类群的多样化数据集中共比对该基因位点，我们对内部转录间隔区（internal transcribed spacer, ITS）区域进行了单独分析。本研究结果与既往研究均表明，桃色层孔菌并不属于狭义的层孔菌属（*Laetiporus* sensu stricto）；尽管基于28S序列的系统发育树得到了不同但无统计支持的拓扑结构，但我们发现桃色层孔菌与非洲物种坦桑尼亚库萨吉孔菌（*Kusaghiporia usambarensis*）之间存在高度支持的系统发育关联。据此，我们结合形态学与分子数据的综合证据，提出新组合（combinatio nova, comb. nov.）：桃色库萨吉孔菌（*Kusaghiporia persicinus*）。桃色层孔菌与坦桑尼亚库萨吉孔菌共享诸多其他层孔菌属物种所不具备的形态特征，包括中生柄担子果、棕至淡粉色的菌盖表面，以及触碰后易变色的菌管层。但坦桑尼亚库萨吉孔菌与桃色层孔菌在担孢子（basidiospore）的大小与形态，以及地理分布上均存在差异。我们为这一常见木腐真菌提供了修订后的分类处理方案。