Three new species of Russula from South China

Abstract

Russula lotus, R. nivalis, and R. purpureoverrucosa are proposed here as new taxa based on morphological and molecular evidences. The new species are described with illustration photographs and line drawings, and compared against related species. Morphologically, R. lotus (subgenus Heterophyllidia, section Heterophyllae, subsection Cyanoxanthinae) is characterized by a medium-sized basidioma with a pale pink to purplish pink pileus whose center area is yellowish white, white to cream white lamellae occasionally forked with lamellulae, a cream white smooth stipe, broadly ellipsoid to ellipsoid basidiospores ornamented with disconnected amyloid warts and inamyloid suprahilar plage, dispersed sulphovanillin (SV)-negative pileocystidia, and the pileipellis with suprapellis cells claw-assembled. Russula nivalis (subgenus Russula, section Russula, subsection Russula) is characterized by a very small pure white basidioma with a pileus 7–12 mm in diameter, abundant clavate pileocystidia and caulocystidia changing purplish red in SV, and broadly ellipsoidal to ellipsoid basidiospores ornamented with strongly amyloid warts and ridges interconnected by fine lines in an uncompleted or completed reticulum, mostly with inamyloid suprahilar plage. Russula purpureoverrucosa (subgenus Incrustatula, section Lilaceinae, subsection Lilaceinae) is characterized by a medium-sized basidioma with a red to grayish magenta pileus slightly areolate in small irregular warts from center to margin, a stipe with the same color and warts as the pileus, white to cream white occasionally forked lamellae with lamellulae, broadly ellipsoidal to ellipsoid basidiospores ornamented with amyloid warts and ridges rarely connected, abundant clavate pleurocystidia covered with thick yellowish incrustations, and the pileipellis with suprapellis cells a typical trichoderm, some of which covered with yellowish incrustations, pileocystidia absent. Phylogenetic analysis of nucleotide sequences of the internal transcribed spacer (ITS) region provided further evidence that the described species belong to the subsections above respectively, and represent new taxa.