Abstract: The progress in the floristic study of the circumpolar Arctic since the 1940s is summarized and a new floristic division of this region is presented. The treeless areas of the North Atlantic and North Pacific with an oceanic climate, absence of permafrost and a very high proportion of boreal taxa are excluded from the Arctic proper. It is argued that the Arctic deserves the status of a floristic region. The tundra zone and some oceanic areas are divided into subzones according to their flora and vegetation. Two groups of subzones are recognized: the Arctic group (including the Arctic tundras proper and the High Arctic) and the Hypoarctic group.
The Arctic phytochorion is floristically divided into sectors: 6 provinces and 20 subprovinces reflecting the regional features of each sector in connection with flora history, physiography and continentality-oceanity of the climate. Each sector is described and differentiated by a set of differential and co-differential species. The peculiarities of the Arctic flora are manifest in different ways in the various sectors, and endemism is not the universal criterion for subdivision.