Phellinus castanopsidis sp nov (Hymenochaetaceae) from southern China, with preliminary phylogeny based on rDNA sequences

Phellinus castanopsidis sp. nov. is described and illustrated from southern China. This species is characterized by resupinate, annual basidiomata, a dimitic hyphal system, hooked hymenial setae, and ovoid to broadly ellipsoid basidiospores that are colorless, thick-walled, weakly dextrinoid, and moderately cyanophilous. Most of these morphological features are shared by Fomitiporia ellipsoidea, P. gabonensis, and P. caribaeo-quercicolus, although in the two latter species, the basidiospores are not dextrinoid. In a phylogenetic perspective, parsimony inferences based on LSU and ITS DNA sequence data show that these four species are closely related, forming a monophyletic clade. Furthermore, this clade is more closely related to the Phellinus ignarius clade (Phellinus s.s.) than to the Fomitiporia clade. Hence, F. ellipsoidea is transferred to Phellinus, and a new combination P. ellipsoideus is proposed also.