Hierarchy of Geobotanical Vegetation Map Units

	Circumpolar Arctic	Alaska Arctic	Upper Kuparuk River Region	Toolik Lake Area	Toolik Lake Grid
Barrens
	B1. Cryptogam, herb barren		1. Anthropogenic barren 2. Lichens on rock	1. Anthropogenic barren 2. Lichens on rock	1. Anthropogenic barren 2. Lichen on rock
	B2. Cryptogam barren complex (bedrock)	B2.1. Lichens on lava (Seward Peninsula)	3. Partially vegetated barren	3. Partially vegetated barrens and revegetated disturbed areas	3. Partially vegetated barren
	B3. Noncarbonate mountain complex
		B3d.1. Acidic mountain complexes (St Lawrence I.)
		B3e.1. Acidic mountain complexes (Brooks Range) B3e.2. Acidic mountain complexes (NW Alaska) B3e.3. Acidic mountain complexes (Kuskokwim Mtns.)
	B4. Carbonate mountain complex
		B4d.1. Nonacidic mountain complexes (Seward Peninsula) B4d.2. Nonacidic mountain complexes (St. Lawrence I.)
		B4e.1. Nonacidic mountain complexes (Brooks Range) B4e.2. Nonacidic mountain complexes (NW Alaska)
Graminoid Tundras
	G1. Rush/grass, forb, cryptogam tundra
	G2. Graminoid, prostrate dwarf-shrub, forb tundra
	G3. Non-tussock sedge, dwarf-shrub, moss tundra	G3.1. Moist nonacidic tundra (N. Arctic Coastal Plain) G3.2. Moist nonacidic tundra (St. Lawrence I.) G3.3. Moist nonacidic tundra (Arctic Foothills, Seward P.)	5. Nontussock-sedge, dwarf-shrub, moss tundra	5. Nontussock sedge, dwarf-shrub, moss tundra	5. Nontussock-sedge 6. Nontussock-sedge, horsetail 7. Nontussock-sedge, Cassiope
	G4. Tussock-sedge, dwarf-shrub, moss tundra	G4.1. Tussock tundra (entire map) G4.2. Lichen-rich tussock tundra (Seward Peninsula) G4.3. Tussock tundra on sands (Arctic Coastal Plain)	4. Tussock-sedge, dwarf-shrub, moss tundra	4. Tussock sedge, dwarf-shrub, moss tundra	4. Tussock-sedge
Prostrate-shrub tundras
	P1. Prostrate dwarf-shrub, herb tundra		10. Prostrate dwarf-shrub, sedge, forb, fruticose –lichen tundra (nonacidic) 9. Prostrate dwarf-shrub, forb, fruticose-lichen tundra (acidic)	10. Prostrate dwarf-shrub, sedge, forb, fruticose-lichen tundra (nonacidic) 9. Prostrate dwarf-shrub, fruticose-lichen tundra	12. Prostrate dwarf-shrub (acidic) 13. Prostrate dwarf-shrub (Dryas octopetala) 14. Prostrate dwarf-shrub (Dryas integrifolia)
	P2. Prostrate/hemiprostrate dwarf-shrub tundra	P2.1. Dry tundra (St Matthew Island)	11. Hemi-prostrate dwarf-shrub, fruticose-lichen tundra 12. Hemi-prostrate and prostrate dwarf-shrub, forb, moss, fruticose-lichen tundra	11. Hemi-prostrate and prostrate dwarf-shrub, forb, moss, fruticose-lichen tundra 12. Hemi-prostrate dwarf-shrub, fruticose-lichen tundra	15. Hemi-prostrate dwarf-shrub (acidic) 16. Hemi-prostrate dwarf-shrub (snowbed < 1m) 17. Hemi-prostrate dwarf-shrub (nonacidic) 18. Hemi-prostrate dwarf-shrub (warm snowbed)
Erect-shrub tundras
	S1. Erect dwarf-shrub tundra	S1.1. Shrubby tussock tundra (NE Alaska) S1.2. Dwarf-shrub, lichen tundra (NW Alaska) S1.3. Dwarf-shrub tundra on volcanic rock (Y-K Delta) S1.4. Dwarf-shrub, lichen tundra (Kuskokwim Mountains)	13. Dwarf- to low-shrub, sedge, moss tundra	13. Dwarf-shrub or low-shrub, sedge, moss tundra	19. Dwarf to low-shrub (birch) 20. Dwarf to low-shrub (willow)
	S2. Low-shrub tundra	S2.1. Willow-birch tundra (entire map) S2.2. Alder shrublands (entire map)	14. Low to tall shrublands	14. Low and tall shrublands	21. Low to tall shrublands (birch) 22. Low to tall shrublands (willow) 23. Low to tall shrublands (water-track) 24. Low to tall shrublands (riparian)
Wetlands
	W1. Sedge/grass, moss wetland	W1.1. Wet acidic coastal complex (N. Alaska) W1.2. Wet nonacidic coastal complex (N. Alaska)
	W2. Sedge, moss, dwarf-shrub wetland	W2.1. Wet acidic complex (N. Alaska, Seward, P.) W2.2. Wet nonacidic coastal complex (N. Alaska)
	W3. Sedge, moss, low-shrub wetland	W3.1. Wet acidic complex with tussock tundra (W. Alaska) W3.2. Wet acidic complex with dwarf-shrub tundra (lower parts of Y-K Delta) W3.3. Wet acidic complex with low-shrub tundra (Y-K Delta) W3.4. Wet acidic complex with dwarf shrub tundra (inland parts of Y-K Delta) W3.5. Wet acidic complex (Nunivak I.) W3.6. Wet nonacidic complex (warmer parts of NW Alaska) W3.7. Wet coastal saline tundra (Y-K delta)	6. Sedge-moss tundra (poor fens) 7. Sedge-moss tundra (fens) 8. Water and herbaceous marsh	6. Sedge-moss tundra (poor fens) 7. Sedge-moss tundra (fens) 8. Water and herbaceous marsh	10. Unvegetated water 11. Herbaceous marsh 8. Sedge-moss tundra (poor fens) 9. Sedge-moss tundra (fens)