Fungi of Cameroon II. Two new Russulales species (Basidiomycota)

Based on fungal material collected in the Mbalmayo Forest Reserve, Cameroon, two Russulaceae for which the specimens Could not be satisfactorily placed to any known species, are described as new to science. Lactarius dewevrei is strikingly characterised by the entire blackish to dark date brown basidiomata and winged basidiospores with broad branched ridges of Plinthogali type, and Russula caeruleoanulata is distinguished by the uniformly pastel yellow color, a blue line at the stem apex as well as the bluing of injured surfaces of the stem. DNA-based phylogenetic placement of the new species was assessed using nucleotide sequences of the partial nuclear large subunit ribosomal DNA (nucLSU rDNA). Molecular analyses Supported the placement of R. caeruleoanulata in R. delica-R. brevipes group of Russula subg. Compacta sect. Compactae, but did not afford a clear-cut placement of L. dewevrei, rather closely related to Lactarius subg. Plinthogali and also subg. Lactariopsis, while BLAST analyses showed similarity with subgs. Lactariopsis, Piperites and Russularia.