Streptocolea atrata (Bryopsida, Grimmiaceae), newly found in western North America, with a review of its global distribution

Streptocolea atrata (Miel. ex Hornsch.) Ochyra & Zarnowiec, a species better known as Grimmia atrata Miel. ex Hornsch., is reported from the Yukon Territory. This is the first record of the species in western North America and the third one from the whole continent. The Yukon plants are briefly characterized and some of their diagnostic characters are illustrated. The global distribution of S. atrata is reviewed and mapped. Comments on the generic distinctness of Streptocolea (I. Hagen) Ochyra & Zarnowiec are presented.