Taxonomy And Phylogeny Of Polyporus S.1.and Related Genera In China

As the type genus of Polyporaceae,Polyporus has been studied since the begining of the 18th century.Species in this genus are widely spread in the world and play an important role in the process of carbon and nitrogen cycling in forest ecosystem.Phylogenetically,Polyporus is proved to be a polyphyletic genus and closely related to Datronia,Echinochaete,Lentinus,Microporus and Pseudofavolus.Recently,based on the phylogenetic and morphological analyses,many species of Polyporus have been combined into four other genera,i.e.Cerioporus,Favolus,Neofavolus and Picipes.Moreover,species of group Polyporellus were treated as members of genus Lentinus.In this study,eight DNA sequences are used to analyze the phylogenetic relationships of Polyporus and its related genera for the first time.Morever,the conserved regions of six DNA sequences are used to analyze the evolutionary relationships of Polyporus and its related genera by using of the Bayesian Evolutionary Analysis Sampling Trees.Fifty-two species,including 25 new species and 3 new records to China,are detailedly described and illustrated in this study,and six previously reported species are ruled out from China.Keys to species of Cerioporus,Favolus,Polyporellus,Neofavolus,Picipes and Polyporus are also provided.Divergence times analysis reveales that the ancestor of Polyporales appeared during the early Cretaceous after angiosperms appearing while evolved to white-rotting and brown-rotting groups during the mid-Cretaceous after angiosperms rapidly diversifying and spreading.In addition,the six main clades of Polyporus and its related genera diverged during Paleocene after angiosperms dominated in the world.Phylogenetically,species of Polyporus and its related genera cluster into six well supported clades,i.e.core polyporus clade,favolus clade,lentinus clade,neofavolus clade,picipes clade and squamosus clade.Among these clades,core polyporus clade contains P.tuberaster,the type species of Polyporus,four other Polyporus spp.and an indeterminate species.Besides,species of genera Favolus,Neofavolus and Picipes cluster in the favolus clade,neofavolus clade and picipes clade respectively,species of group Polyporellus cluster in the lentinus clade with Lentinus species while several species of group Polyporus and Melanopus cluster in the squamosus clade with species of Datronia,Datroniella,Echinochaete,Mycobonia,Neodatronia and Pseudofavolus.Morphologiacal analyses indicate that species in the core polyporus clade have fleshy(when fresh)to brittle(when dry)basidiocarps,light colored stipe,inflated hyphae,monomitic hyphae systerm in context or trama and absence of cystidioles.Species in the favolus clade have soft coriaceous to coriaceous(when fresh)and brittle to corky(when dry)basidiocarps,light colored stipe,radially striate pileus,sickle-shaped to subulate cystidioles,absence of agglutinated hyphae on pileal surface and distribution mainly in tropical to south subtropical areas.Polyporoid species in the lentinus clade have squamaceous or fluffy pileal surface,central stipe without dark colored cuticle,inflated hyphae and absence of cystidioles.Species in the neofavolus clade have soft coriaceous to coriaceous(when fresh)and corky to hard(when dry)basidiocarps,hyaline to brown cutis on pileal surface,absence of cystidioles and distribution mainly in temperate to north subtropical areas.Species in the picipes clade have corky to coriaceous(when fresh)and hard(when dry)basidiocarps,uninflated hyphae,thick-walled skeleto-binding hyphae with a narrow lumen to subsolid in mature specimens,stronly interwoven dendroid skeleto-binding hyphae in trama.Species in the squamosus clade have various basidiomata and hyphae structures,but for Polyporus spp.in this clade,they have fleshy,soft corky to to coriaceous(when fresh)and corky to slightly brittle(when dry)basidiocarps,brittle tubes in dried condition,brown to black stipe and frequent absence of cystidioles.After analyzing the morphological and phylogenetical results,species in core polyporus clade,favolus clade,neofavolus clade and picipes clade are respectively combined into the genera Polyporus s.str.,Favolus,Neofavolus and Picipes.Genus Polyporellus is reused to admit polyporoid species in the lentinus clade.Because species in the squamosus clade have many obvious differences between different genera,genus Cerioporus is prefered to merely combine Polyporus species in squamosus clade.