Range Extensions of Orthotrichum pallens Brid. in North America

Abstract

Orthotrichum pallens Brid. is reported new to temperate and arctic Alaska, to Corn- wallis Island, arctic Canada, and to West Greenland. It is postulated to have survived the last glaciation in three refugia in arctic Alaska, in northern Ellesmere Island, and central East Green- land, as well as south of the major area of glaciation. Ten years have passed since Vitt (1973) published his revision of the genus Orthotrichum in North America, north of Mexico. In his paper, 0. pallens Brid. was considered restricted to high elevations in the coniferous forests of western North America, and the southern boreal zone across Canada. Since then it has been reported from Ellesmere Island (Brassard 1976), Greenland (Lewinsky 1977a) and Bathurst Island (Miller & Ireland 1978). During a present revision of the Orthotrichum specimens in ALA, ALTA, C, CANM and NY, it was also observed from temperate and arctic Alaska, from Cornwallis Island, arctic Canada, and from West Greenland. The known distribution at present thus comprises