Kaziboletus, a new boletoid genus of Boletaceae associated with Shorea robusta in Bangladesh

A bolete putatively associated with Shorea robusta, morphologically resembling Leccinum, Leccinellum, and Spongispora but distinct genetically, was collected in Bangladesh. DNA analyses of four gene fragments (nrLSU, TEF1-α, RPB1, and RPB2) placed this bolete in the subfamily Leccinoideae of the family Boletaceae, but representing a distinct generic lineage. Phylogenetically, the new bolete is sister to a clade comprising morphologically closely related stipitate-pileate genera: Leccinum, Leccinellum, and Spongispora; and sequestrate genera: Chamonixia, Octaviania, Rossbeevera, and Turmalinea. Nevertheless, some morphological differences and host preference together with the molecular inferences distinguish the new bolete from Leccinum, Leccinellum, and Spongispora. This lineage is described as a monotypic genus Kaziboletus and is typified by K. rufescens. It is circumscribed by a context that turns pale red or reddish orange when exposed, a scurfy stipe with conspicuous longitudinal striations from the apex to just above the base, elongated to cylindrico-fusoid smooth basidiospores 17–19 × 5.5–6.5 μm, the presence of sparse hymenial cystidia, an epithelium pileipellis, and putative ectomycorrhizal with S. robusta in Bangladesh. Morphological descriptions, illustrations, line drawings, and comparisons with allied taxa/genera are provided. A key to the genera morphologically similar to Kaziboletus is also provided.