Subdivision of the Arctic into 28 sectors follows mainly the division used in the Pan Arctic Flora (PAF) project. In a few cases some islands are separated from their mainland in the beginning, thus representing very small sectors. Some of them have now been united like in the PAF project, for example Jan Mayen with Arctic Iceland and Bear Island with Svalbard. Others, like the Beringian Islands are still kept separate from the mainland on both sides. - <a href="http://www.caff.is/assessment-series/32-pan-arctic-checklist-of-lichens-and-lichenicolous-fungi" target="_blank"> Pan-Arctic Checklist of Lichens and Lichenicolous Fungi (2011)</a>

Appendix 10.1. Updated Panarctic Lichen Checklist as used for the calculations (version March 2013) with data on preferred substrate, growth form (crustose, squamulose, foliose, fruticose), rarity of species within and outside the Arctic, occurrence in the low and high Arctic and occurerence in the floristic provinces.

Appendix 10.2. Data on diversity of lichens and lichenicolous fungi in the Arctic and separately for the sectors of the Arctic (Beringia, Canada, North Atlantic, European Russia, W and E Siberia) and the single floristic provinces: numbers of species, numbers of species in the low and high Arctic, percentage of species with respective growth form (crustose, squamulose, foliose, fruticose), the estimated number of missing crustose lichen species (explanations below), percentage of species on the respective substrate on which the lichen species grow, and rarity of species within and outside the Arctic.