We investigated the phylogenetic relationship in cyanolichen family Placynthiaceae to the current genetic delimitation where the monopypic Collolechia is currently accept as distinct, based on differences in ascospores, ascus apex characteristics and the leprose thallus. Bayesian and maximum likelihood phylogenetic analyses of two sequence marker datasets confirmed that Collolechia caesia is nested within Placynthium, and should be called Placynthium caesium.