Two new species in the Russula (Russulaceae, Basidiomycota) crown clade from Indian Himalaya

Abstract

Two species, namely Russula adwanitekae A.Ghosh, K.Das & Buyck sp. nov. and Russula purpureozonata K.Das, A.Ghosh & Buyck sp. nov. are proposed herein as new mushroom taxa from the Indian Himalaya based on their morphological features and ITS-based phylogenetic inferences. Both species belong to the crown clade of Russula subgenus Russula but with affinities to different subsections, viz. subsect. Laricinae Romagn. and subsect. Decolorantes Maire, respectively. Russula adwanitekae sp. nov. was collected in mixed temperate forests where it is most likely associated with conifers. It is distinct from several similarly looking, small, mild species with dark spore print and reddish lilac, orchid purple or greyish to deep magenta colored pileus in subsect. Laricinae by its sequence data (nrITS) or geographic distribution. Russula purpureozonata sp. nov. associates with Abies densa Griff., and possesses all typical features of Decolorantes, viz. the amyloid suprahilar spot on the spores, presence of pileogloeocystidia, the reddening then blackening context, equal lamellae and colored spore print. It reminds of North American R. californiensis Burl. and R. magna Beardslee under the microscope but has distinctly smaller spores and differs further in the unique coloration and concentrically zonated pileus margin. Macro- and micromorphological features are illustrated for both species. Their habitats, distributions and relationships with allied species are discussed.