Circumscription and Taxonomic Arrangement of Nigroboletus roseonigrescens Gen. Et Sp. Nov., a New Member of Boletaceae from Tropical South–Eastern China

Nigroboletus is proposed as a novel genus in family Boletaceae, subfamily Boletoideae, to include N. roseonigrescens, a new boletoid species from tropical environment in south–eastern China. Detailed morphological description, color pictures of both fresh basidiomes in habitat and dried material along with photomicrographs and line drawings of the main anatomical features are provided, supported by a comprehensive phylogeny based on multigene molecular analysis (nrITS, nrLSU, rpb1, rpb2 and tef1-α datasets). Taxonomic placement and evolutionary relationships of Nigroboletus are investigated.