Introduction
Barren Complexes: B2.1B2.1 Lichens on Lava (Seward Peninsula) - B3d.1B3d.1 Acidic mountain complexes (St. Lawrence Is.) - B3e.1B3e.1 Acidic mountain complexes (Brooks Range) - B3e.2B3e.2 Acidic mountain complexes (NW Alaska) - B3e.3B3e.3 Acidic mountain complexes (Kuskokwim Mtns.) - B4d.1B4d.1 Nonacidic mountain complexes (Seward Peninsula) - B4d.2B4d.2 Nonacidic mountain complexes (St. Lawrence Is.) - B4e.1B4e.1 Nonacidic mountain complexes (Brooks Range) - B4e.2B4e.2 Nonacidic mountain complexes (NW Alaska)
Non-Tussock Graminoid Tundras: G3.1G3.1 Moist nonacidic tundra (N. Arctic Coastal Plain) - G3.2G3.2 Moist nonacidic tundra (St. Lawrence Is.) - G3.3G3.3 Moist nonacidic tundra (Arctic Foothills, Seward Peninsula)
Tussock Graminoid Tundras: G4.1G4.1 Tussock tundra (entire map) - G4.2G4.2 Lichen-rich tussock tundra (Seward Peninsula) - G4.3G4.3 Tussock tundra on sands (Arctic Coastal Plain)
Prostrate Dwarf-Shrub Tundras: P2.1P2.1 Dry tundra (St. Matthew Is.)
Erect Dwarf-Shrub Tundras: S1.1S1.1 Shrubby, tussock tundra (NE Alaska) - S1.2S1.2 Dwarf-shrub, lichen tundra (NW Alaska) - S1.3S1.3 Dwarf-shrub tundra on volcanic rock (Yukon-Kuskokwim Delta) - S1.4S1.4 Dwarf-shrub, lichen tundra (Kuskokwim Mtns.)
Low-Shrub Tundras: S2.1S2.1 Willow-birch tundra (entire map) - S2.2S2.2 Alder shrublands (entire map)
Wetlands: W1.1W1.1 Wet acidic coastal complex (N Alaska) - W1.2W1.2 Wet nonacidic coastal complex (N Alaska) - W2.1W2.1 Wet acidic complex (N Alaska, Seward Peninsula) - W2.2W2.2 Wet nonacidic complex (Subzone D, N Alaska) - W3.1W3.1 Wet acidic complex with tussock tundra (W Alaska) - W3.2W3.2 Wet acidic complex with dwarf-shrub tundra (lower parts of Yukon-Kuskokwim Delta) - W3.3W3.3 Wet acidic complex with low-shrub tundra (Yukon-Kuskokwim Delta) - W3.4W3.4 Wet acidic complex with dwarf-shrub tundra (inland parts of Yukon-Kuskokwim Delta) - W3.5W3.5 Wet acidic complex (Nunivak Is.) - W3.6W3.6 Wet nonacidic complex (warmer parts of NW Alaska) - W3.7W3.7 Wet coastal saline tundra (Yukon-Kuskokwim Delta)

S1.3 Dwarf-shrub tundra on volcanic rock (Y-K Delta)

Erect and prostrate dwarf-shrub communities (comm. 49) on volcanic outcrops, commonly in complexes with rock outcrops and alder-dominated drainages (comm. 51). Yukon Delta, Nunivak Island, Subzone E.

Plant Communities:

Community 49

Site 63, 32 (Swanson et al. 1986) (Nunivak Island).

Erect and prostrate dwarf shrub: Betula nana, Salix fuscescens, Empetrum nigrum, Vaccinium vitis-idaea;
Sedge: Carex bigelowii;
Lichen: Cladina rangiferina, Cladina arbuscula, Cetraria islandica

Community 51

Alder types; green alder shrub thicket (Hanson 1953); Map Unit 22 -tall shrub hillside (Racine and Anderson 1979); Releves C15,C18,QC25 (Raynolds et al. 2002) (Seward Peninsula).

Map Unit 8, subalpine scrub (Talbot et al. 1985); Map Units D2,D5,F1,F2 (Wibbenmeyer et al. 1982) (Yukon-Kuskokwim Delta).

Low shrub: Alnus viridis ssp. fruticosa, Spiraea stevenii;
Grass: Calamagrostis canadensis;
Fern: Dryopteris expansa