Morphological and phylogenetic evidence reveal two new Pseudohydnum (Auriculariales, Basidiomycota) species from Guangxi and Xizang, China

Pseudohydnum (Auriculariales) is characterized by gelatinous, hydnoid basidiomata and longitudinally septate basidia. Currently, 26 species and one subspecies are accepted worldwide with molecular evidence, including two new species described here. In this study, specimens from Guangxi, Xizang, and Jilin provinces, China, were examined using morphological and phylogenetic analyses based on ITS 1– 5.8 S – ITS 2 – nLSU sequences.

The phylogeny resolves the genus as a well-supported monophyletic group. Pseudohydnum umbrosum is newly recorded from China. Two new species are described and illustrated as P. fusiformis from Xizang, characterized by olivaceous buff to clay-pink basidiomata, association with Abies at high elevations (above 3200 m), and the presence of fusiform cystidia — a feature previously known only from P. cystidiatum within the genus; and P. rhododendri from Guangxi, characterized by shell-shaped basidiomata with a pale mouse-gray pileal surface, the presence of cystidioles, and growing on living Rhododendron.

The discovery of these new taxa and the new record further highlight China as a significant diversity center for Pseudohydnum.