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)

S2.2 Alder shrublands (entire map)

Low-shrub communities (comm. 51) with closed alder canopies in drainages and valleys, and at treeline. Foothills of the southern Brooks Range, Seward Peninsula mountains, and Kuskokwim Mountains, Subzone E.

Plant Communities:

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