XVI International Botanical Congess

The Russulales consists of agaricoid and gasteroid taxa of basidiomycetes related to Russula and Lactarius. Because there have been no molecular phylogenetic studies of the Russulales, attempts at formulating natural phylogenies for hypogeous, gasteroid and agaricoid taxa have met with difficulty. In this study, large subunit rDNA was used to infer phylogeny among members of the Russulales including tropical pleurotoid and annulate taxa and gasteroid genera. These results show that Russula is polyphyletic, with one group being derived from Lactarius and one group arising separately. Lactarius appears to be monophyletic. Gasteroid genera are scattered throughout the order with Macowanites, Gymnomyces, Cystangium and Martellia clustered within Russula clades while Zelleromyces and Arcangeliella appear within Lactarius. All of the gasteroid taxa appear to be polyphyletic and fit in established infrageneric taxa of Russula and Lactarius. These results suggest that synonomy of gasteroid genera into Russula and Lactarius may be justifiable.Steven L. Miller