Five fungal isolates, tentatively identified as belonging to Thysanophora, were re-examined to confirm their generic placement. DNA sequences from multiple loci were determined and compared to homologous sequences from other fungi. The Thysanophora-like isolates belong in the genus Penicillium on the basis of phylogenetic analysis of their gene sequences. Because these isolates have unique phylogenetic positions within Penicillium and have unique phenotypes we describe them as the new species P. boreae, P. subarcticum and P. canariense spp. nov. In addition, P. pullum sp. nov. is described for NRRL 721, which served as the typical isolate of P. fuscum in the monographic studies of Raper & Thom and Ramirez; however, the name P. fuscum has been applied and neotypified using a different specimen and NRRL 721 is markedly different phylogenetically from the neotype of P. fuscum.