Observations in the field and the results of inoculation experiments show that perennial needle rust of fir (Abiesspp.), known asPeridermium pseudo-balsameum(Diet. & Holw.) Arth. & Kern, is caused byUredinopsis hashiokaiHirats. f. andU. pteridisDiet. & Holw. (U. macrospermaMagn.), which complete their life cycles on bracken fern (Pteridium aquilinum(L.) Kühn var.lanuginosum(Bong.) Fern.). The pycnial and aecial states ofUredinopsis hashiokaiare described, and for the first time the life histories ofU. hashiokaiandU. pteridisare presented. The two species are indistinguishable from each other in life history, host relationship, and morphology of most of the spore states; they differ from each other in their geographical distribution and in the morphology of their urediniospores. It remains unknown which of the two species ofUredinopsisrepresents the perfect state ofPeridermium pseudo-balsameum.Uredinopsis asperaFaull proved to be a later synonym ofU. hashiokai. U. hashiokaiis noteworthy because of its similarity toU. pteridis, and both species are unusual in development of their spore states on fir, particularly in the long periods required for maturation of the aecia, which are produced from localized, perennial mycelium 4 to 11 months after infection inAbies lasiocarpa(Hook.) Nutt. andA. grandis(Dougl.) Lindl. respectively.