Lichens from Bathurst Inlet Region, Northwest Territories, Canada

Abstract

Reported from Bathurst Inlet region in the central northern conti- nental arctic of North America are 214 species representing 223 taxa. The majority are circumpolar species, seven are western arctic, three are possibly eastern arctic. Pertusaria excludens is reported from the American arctic and Peltigera occiden- talis is confirmed for North America. New combinations are Aspicila arctica (Lynge) Thoms. and Aspicilia bennettii (Lynge) Thoms. Bathurst Inlet, located in the central northern edge of the continental arctic portion of North America, is important in providing information on the extent of distribution of the American arctic lichens, such as whether or not the ranges extend that far from the eastern arctic or represent easterly ranges of the Beringian, western arctic, elements in the flora. The comparative inaccessibility of this area has left its cryptogamic flora unstudied until now. The nearest lichen studies are those to the west at the Anderson River drainage (Ahti et al. 1973), to the south in the vicinity of Great Slave Lake (Thomson et al. 1969) and to the southeast in the Thelon River region (Scotter & Thomson 1966). Bathurst Inlet is on the mainland of the western Canadian Arctic, roughly between the mouth of the Mackenzie River and Boothia Peninsula. The inlet is a complex submerged valley that penetrates from the east end of Coronation Gulf in a southeasterly direction about 200 km into the barren grounds. The Bathurst Inlet area lies wholly within the physiographic division of the Canadian Shield. Bird and Bird (1961) described the physiographic regions defined below. The Inlet itself and its adjacent lowlands they regard as a long narrow southward extension of the Coronation Gulf lowlands penetrating the Canadian Shield, which forms plateaus to east and west: the Tree River Uplands, Wilberforce Hills and Contwoyto Plateau to the west, and the Bathurst and Buchan Uplands to the east. The Contwoyto Plateau is in general high (450 m elev.), gently rolling, and mantled with drift, with the Wilberforce Hills as its rough dissected edge. The Tree River Upland is a lower, dissected granite plateau of smoothed rock-knob hills penetrated by deep valleys into which drift deposits have been washed. The Buchan Upland northeast of Bathurst Inlet is similar to the Tree River Upland although somewhat lower, a granite peneplain eroded into bare rock-knob hills. Drift washed into the valleys supports damp tundra, although many valleys are blocked, forming elongated or cruciform lakes. The Bathurst Upland to the southeast corresponds to the Contwoyto Plateau; near Gordon Bay this upland surface is deeply dissected. Farther south, to the east of Western River, there is less dissection, but both areas are rocky. The