XVI International Botanical Congess

ITS sequences from Suillus s.l. and Rhizopogon, the two largest genera in the suilloid group, have been determined and used for phylogenetic analyses. Most larger clades and grades within these genera, and the radiation at large, are associated with white or red pine subgroups, Pseudotsuga, or Larix, but these specific associations are convergent. Timing of the suilloid radiation is estimated at 60 to 35 mya, which is recent relative to the origin of genera in the Pinaceae. This timing difference and the convergence of host-pattern argues against co-cladogenesis. Nevertheless, host fidelity within the suilloids is high over evolutionary time scales and host-switching events are rare and usually restricted to a suite of closely related host genera.