XVI International Botanical Congess

Rare mosses comprise about 11% of the Canadian moss flora. Temperate species are dominant (59%), with small, nearly equal percentages of arctic, montane, and boreal species. Compared with the non-rare mosses, the rare species are significantly under-represented in boreal species and over-represented by temperate mosses. British Columbia has the largest number of rare mosses, harboring nearly 50% of the total, Ontario is also important. Within ecozones, the rare mosses show an uneven distribution: the largest numbers are found in the the western Cordillera and moderate numbers are found in the Boreal Shield and Atlantic Maritimes. Acrocarpous mosses are over-represented as compared with the non-rare species. Rare mosses are over-represented in the Funariales, and slightly under-represented in Isobryales and Pottiales. Comparisons of attributes with rare mosses within provinces are presented.