New species and distribution records for Clavulina (Cantharellales, Basidiomycota) from the Guiana Shield, with a key to the lowland neotropical taxa.

Three new and one previously described species of Clavulina (Clavulinaceae, Cantharellales, Basidiomycota) are reported from the central Guiana Shield region from tropical rainforests dominated by ectomycorrhizal trees of the leguminous genus Dicymbe (Fabaceae subfam. Caesalpinioideae). We provide morphological, DNA sequence, habitat, and fruiting occurrence data for each species. The new species conform to a generic concept of Clavulina that includes coralloid, branched basidiomata with amphigenous hymenia, basidia with two or 2-4 incurved sterigmata and postpartal septa present or absent, and smooth, hyaline, guttulate basidiospores. Placements of the new species in Clavulina were corroborated with DNA sequence data from the internal transcribed spacer and large subunit of the nuclear ribosomal repeat, and their infrageneric relationships were examined with phylogenetic analyses based on DNA from the region coding for the second largest subunit of DNA-dependent RNA polymerase II (rpb2). To facilitate future studies of the genus in the neotropics, a key is provided for all Clavulina species described from the lowland neotropics.