Three new species of Russula subsect. Cyanoxanthinae from subtropical China (Russulales, Russulaceae)

Three new species belonging to Russula subsect. Cyanoxanthinae, namely R. purpureogrisea, R. subpallescens, and R. wuyishanensis, are described from subtropical China based on combined morphological and molecular evidence. Morphologically, R. purpureogrisea is distinguished by a dark greyish-ruby to greyish-brown pileus, close lamellae with lamellulae, a white context that remains unchanging when bruised, and basidiospores with ornamentation composed mostly of obtuse-conical isolated warts, occasionally connected by fine lines or low ridges, occasionally forming a subreticulum locally.

Russula subpallescens is recognized by a pinkish-white pileus, adnate lamellae of equal length, an unchanging context, a white stipe that develops pale yellow to maize-yellow patches with age or long after bruising, and basidiospores with ornamentation composed of dispersed warts, frequently connected by short lines, nearly subreticulate. Russula wuyishanensis features a variable pileus color ranging from reddish-grey to purplish-brown, three types of lamellulae, a white stipe occasionally with rust-colored patches, a white context turning yellowish-brown when bruised, and basidiospores with ornamentation predominantly consisting of isolated warts, partially connected by short lines or ridges, occasionally subreticulate.

The independent taxonomic status of these three novel taxa is strongly supported by multi-locus phylogenetic analyses based on four gene regions (ITS, LSU, mtSSU, and rpb 2). Detailed descriptions and morphological photographs of the new species are provided herein.