Russula verrucospora sp. nov. and R. xanthovirens sp. nov., two novel species of Russula (Russulaceae) from southern China

Two novel species of Russula subgenus Heterophyllidia, collected from Guangdong Province, P. R. of China, are described and illustrated based on both morphology and phylogenetic analyses of ITS sequences. Russula verrucospora sp. nov. is characterized by a combination of unequal lamellae, verrucose basidiospores, presence of robust caulocystidia, and pleurocystidia changing to reddish-brown in sulphovanillin (SV). R. xanthovirens sp. nov. is phylogenetically closely related to R. aureoviridis within subsection Virescentinae, but it can be separated from the latter by its much thicker pileipellis which is distinctly divided into two layers and orthochromatic in cresyl blue, ellipsoid to globose subterminal cells, bigger basidiospores with higher warts and ridges, and much longer pleurocystidia and cheilocystidia. Both morphological and molecular data consistently verify that R. verrucospora and R. xanthovirens are new to subg. Heterophyllidia. The differences among these two novel species and their related taxa are discussed.