A new species of Lactifluus (Russulales, Agaricomycetes) from the Brazilian caatinga semiarid region

Lactifluus (Russulaceae) is a genus of ectomycorrhizal fungi, comprising mostly tropical milkcaps with more than 150 described species. In Brazil 24 milkcap species are known, but only three of these are described from the north-eastern region. The north east of Brazil is composed of different types of habitats, namely Atlantic Forest, part of the Cerrado ecoregions and the Caatinga Domain. From the semiarid Caatinga Domain, Lf. caatingae is described in this paper as a new species, using morphological and molecular data. The new species is characterised by the rusty brown to brownish orange basidiomes, subglobose to broadly ellipsoid, rarely globose basidiospores with verrucose ornamentation composed of warts up to 0.6 mu m, that are interconnected by fine lines forming a complete reticulum, and the lampropalisade structure of the pileipellis. Phylogenetic analysis shows that Lf. caatingae belongs to L. subg. Lactariopsis, more specifically to an unnamed clade containing exclusively Neotropical representatives