The alpine flora of Teresa Island, Atlin Lake, B.C., with notes on its distribution

Abstract

A comprehensive inventory of the vascular plants is provided for the alpine zone of Teresa Island in Atlin Provincial Park, British Columbia. A total of 161 taxa were identified from collections made during a research program conducted in the summers of 1974, 1975, and 1976. Of these taxa Arnica louiseana var. frigida, Draba lactea, Lupinus kuschei, Oxytropis huddelsonii, Poa lettermanii, Senecio sheldonensis, Senecio yukonensis, and Stellaria longipes var. edwardsii have a restricted or otherwise interesting distribution in British Columbia.Preliminary observations indicate that the local distribution of all the taxa is controlled by three environmental gradients: snow duration, moisture, and topography. Five different alpine habitat types are recognized as a result of different combinations of these gradients. These habitat types are (1) fell-fields and boulder fields, (2) meadows and shrub fields, (3) snow beds, (4) seepage sites, and (5) drainage areas. The habitat types and relative abundance of each taxon are listed.