The Brooks Range describes a majestic are from east to west across Alaska north of the Arctic Circle. It is part of the Arctic Mountain System, which forms the watershed between the Arctic Ocean and the Bering Sea, and as an orographic continuation of the Mackenzie group of Canada is a northwesterly extension of the Rocky Mountain System. A few peaks reach 10,000 ft., but the majority do not exceed 8,000, and despite the cold, because of low precipitation only a few of the higher valleys at the eastern end of the range have glaciers. The Brooks Range is of particular interest for botanical study because it is still virtually unexplored country. Owing to the inaccessibility of the region and to the difficulty of working there, few botanists have collected in this area. The south slopes of the range form the boundary of two broadly defined physiographic provinces: the Arctic, or Northern Mountain system where tundra prevails and the Central and Plateau region where boreal forests are established. Here, then, is a transitional area, where northern forests and arctic tundra merge and where it is to be expected that both arctic and boreal bryophytes, including many rare species, will be found. Alaska suffered less glaciation in the last ice age than other northern parts of North America. A broad belt extending from east to west across the middle of Alaska is believed to have been virtually unglaciated during the Pleistocene (Capps, 1931). The Bettles-Wiseman region of the Brooks Range is located at the northern limit of the central unglaciated band, and it is believed that many plants now occupying this area may have persisted there