Cellulariella warnieri (Basidiomycota, Polyporales) and its doubles

Species of Polyporales with a lamelliform hymenophore were traditionally classified in the genus Lenzites, until recent phylogenetic analyses revealed their affinities with various poroid lineages, leading to the re-classification of most of them. Nevertheless, the phylogenetic relationships of the lamellate Lenzites warnieri Durieu & Mont. have yet to be resolved. The recent erection of Cellulariella Zmitr. & V. Malysheva to encompass L. warnieri and L. acuta did little to disentangle the cross-synonymies between lamellate polypores of the Trametes group. To clarify the phylogenetic affinities of L. warnieri, we combined molecular data based on five markers (LSU, ITS, EF1-, RPB1, RPB2) with morphological features of various collections belonging to the Trametes clade. In Bayesian phylogenetic reconstructions based on RPB1, RPB2 and EF1-, L. warnieri has an unresolved position on globally poorly supported cladograms. Conversely, phylogenetic analyses of the combined (ITS+LSU) sequences support a monophyletic clade encompassing L. warnieri and L. acuta, which forms a sister group, within a broader clade encompassing Leiotrametes, Pycnoporus and the sub-clade T. ljubarskyi -T. cingulata. These phylogenetic results are also supported by micromorphological data. Here we redefine the genus Cellulariella based on the moderate amount of scarcely branched, not flagelliform binding hyphae in the context, the pointed and fusiform hyphal ends protruding through the hymenium and a strictly lamelliform (lenzitoid) hymenophore. A lectotype is designated for Cellulariella warnieri. The name Lenzites acuta has also been misapplied to a species of Leiotrametes, possibly identical to Lenzites tenuis. Lenzites tenuis is here recombined as Leiotrametes tenuis comb. nov.