Anacolia menziesii sensu lato (Bartramiaceae) is a common and widespread moss in western North America that has been treated as either a single variable species or two distinct taxa, A. menziesii s.s. and A. baueri, with the two variously interpreted as species or subspecies. Interpretation has been hampered historically because the primary character used to separate the two entities, capsule shape, is absent on most specimens of this dioicous moss, and gametophytes have not yielded characters that can be used to separate the two putative entities with confidence. Here, we quantified previously categorical traits to test whether morphological characters are continuous across the geographic range or whether discrete morphological groups exist within A. menziesii s.l. We found that quantitative sporophyte characters replacing analogous categorical characters support the recognition of two entities, and that quantitative gametophyte characters also support the recognition of two entities. Furthermore, the two morphologically defined entities are overlapping geographically but have distinctive ecological niches. This provides strong evidence supporting the recognition of two species and provides new tools for separating sterile material.