Contrasting evolutionary patterns in two sister genera of macrofungi: Lactarius and Lactifluus

The Russulaceae family (Basidiomycota) comprises four agaricoid genera (with cap, gills and stipe), including the milk cap genera Lactarius and Lactifluus. Lactifluus mainly consists of tropical species and has a large cryptic diversity, while Lactarius has a more temperate distribution. Our hypothesis is that Lactifluus evolved genetically faster but is morphologically more stable and that morphological variation is more common in the genetically slower evolving genus Lactarius. In this study, expertise, knowledge and material of the research group Mycology from Ghent University will be used to investigate the contrasting evolutionary dynamics of Lactarius and Lactifluus. We will construct a comprehensive phylogeny of the Russulaceae genera, with emphasis on the strongly underrepresented genus Lactifluus. Furthermore, we will apply phylogenetic comparative analyses to test ecological and morphological macroevolutionary hypotheses in a statistically correct way. Using these techniques, we can obtain insights into the occurrence of cryptic speciation, the causes of different rates of speciation, the ancestor and the origin of both genera; which will result in a thorough understanding of the historical evolution of the Russulaceae.