Lasallia is a genus of lichen-forming fungi in the family Umbilicariaceae. The genus was circumscribed by François Victor Mérat de Vaumartoise in 1821. The genus name Lasallia honours of Mr. Lasalle (born around 1820), who was a French gardener and botanist, who worked in Fontainebleau. Early molecular phylogenetics analysis of internal transcribed spacer DNA showed that the genus was monophyletic.
High performance liquid chromatography analysis of several Lasallia species revealed a number of secondary metabolites in this genus, including gyrophoric acid, lecanoric acid, umbilicaric acid, 7-chloroemodin, valsarin, skyrin, hiascic acid, and ovoic acid.