Abstract
Rubinosporus, a new bolete genus from tropical forests of Thailand is introduced with R. auriporus as the type species. The genus is unique among Xerocomoideae in producing dark ruby spore deposits. It can be differentiated from all other Boletaceae genera by the following combination of characters: pileus surface evenly covered with matted tomentum; stipe surface with evenly scattered minute squamules; golden yellow tubular hymenophore, which is relatively thin especially when young; unchanging surfaces and context when bruised or cut; smooth, broadly ellipsoid basidiospores; and dark ruby spore deposits. The Boletaceae-wide and Xerocomoideae-wide phylogenetic analyses based on four-gene data sets (atp6, cox3, rpb2, and tef1) support Rubinosporus as monophyletic and places it in Boletaceae subfamily Xerocomoideae. Full descriptions and illustrations of the new genus and species are presented.