The species of Psilocybe sect. Psilocybe, formerly classified in the genus Deconica, were investigated using morphology, mating behaviour and RAPD analysis. Psilocybe inquilinus and P. crobula do not seem to be closely related. Based on the morphology, two varieties could be accommodated in P. subviscida, namely as vars. subviscida and velata. The mating group of P. montana is characterized by rather thick-walled, dark spores with a fairly large germ-pore. Putative representatives of P. muscorum and P. physaloides freely interbreed with typical P. montana, and, consequently, these taxa are considered to represent one variable species. The ex-type strain of P. chionophila did not mate with isolates of P. montana. One collection of P. chionophila from a lowland habitat, morphologically resembling P. montana, was found to be interfertile with the ex-type strain of P. chionophila, but not with P. montana. We identified several collections as P. magica, which is morphologically similar to P. schoeneti. Mating studies showed that these specimen belong to the same biological species, but failed to mate with the ex-type of P. schoeneti.