Lecidea rubrocastanea T. Sprib. & Printzen is described as new from conifer bark and wood in montane valleys of inland British Columbia, Idaho, Montana, Oregon and Washington State. It is characterized by its combination of a crustose olivaceous thallus lacking secondary lichen substances, small, dark burgundy-red or maroon apothecia, dark-capped paraphyses, Lecidella-type ascus, small, thin-walled ascospores, and bacilliform conidia. The generic affinities of the species based on analysis of ITS DNA are unclear, but it has numerous morphological traits in common with Japewia.
