XVI International Botanical Congess

Lecanora is the largest genus of the family Lecanoraceae and includes several monophyletic groups. Our studies concentrated on the placodioid taxa and the crustose Lecanora sensu stricto. The latter assemblage includes species containing atranorin and having a special type of apothecial anatomy. The phylogeny of both groups is discussed and the occurrence of representatives of different clades in arid regions is shown. The species composition and their relations to species occurring outside the Sonora desert region differs between both groups. The phytogeography of the Lecanora flora in the Sonora desert region is compared to the flora in other arid areas.