Nugget moss (Microbryum vlassovii) COSEWIC assessment and status report: chapter 9

Special Significance of the Species

Microbryumvlassovii is extremely rare in North America, and appears rare globally. The British Columbia populations represent two of three known occurrences of this species in North America. Considering the number of collections examined, it is much rarer than other dryland bryophytes in the region. Lacustrine banks are also the only habitat known for a number of other apparently rare Canadian species of mosses, including Pottia wilsonii, Crossidium seriatum, Desmatodon guepinii, and Grimmia plagiopodia (McIntosh 1986). Except for the latter species, all are listed in the list of rare mosses of Canada (Belland 1998). Other more common dryland moss species have their main populations on lacustrine banks. These include Tortula brevipes, Aloina bifrons, and Aloina brevirostris. Many unusual and probably rare crustose and tiny foliose lichen species are also found primarily on lacustrine bank surfaces.

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