Functional type Height (cm) Patch size (m2) Description & distributional patterns
Lichens 0–5 0.001–100 Diverse nonvascular plants consisting of fungal and algal symbionts, often distinguished by growth form (foliose, fruticose, crustose) or color group. Intermixed “reindeer lichens” (Cladonia spp.) and other fruticose taxa (e.g., Flavocetraria, Alectoria, and Bryoria spp.) can form extensive mats on undisturbed, well drained sites.
Bryophytes 0–5 0.001–100 Nonvascular plants including mosses and liverworts. Found throughout Arctic; common mesic taxa include branched “feathermosses” (e.g., Hylocomnium splendens, Pleurozium schreberi) and single-stemmed mosses (e.g., Dicranum and Polytrichum spp.). Peat mosses (Sphagnum spp.) can form continuous carpets in wet areas. Liverworts much less abundant, but form extensive cryptogamic crusts in High Arctic.
Graminoids 10–70 0.01–0.25 Sedges and grasses. Sedges common throughout tundra except in coldest parts of High Arctic. Tall cottongrass (Eriophorum angustifolium) and water sedge (Carex aquatilis) often dominate wet sites. Large areas of tussock tundra dominated by Arctic cottongrass (Eriophorum vaginatum) occur in Low Arctic on mesic soils. Grasses superficially resemble sedges and occur throughout Arctic, but cover is usually low; most common on floodplains and disturbed sites. Pendantgrass (Arctophila fulva) is a common marsh species.
Forbs 0–50 0.01–0.05 Diverse group of non-graminoid herbaceous flowering plants found throughout the Arctic, but cover is typically low. Common forbs include Arctic lupine (Lupinus arcticus), Arctic sweet coltsfoot (Petasites frigidus), and “cushion” plants such as purple mountain saxifrage (Saxifraga oppositifolia).
Deciduous shrubs 0–500 0.01–100 Multi-stemmed, broadleaf woody plants; common erect species include dwarf birch (Betula nana), diamondleaf willow (Salix pulchra), and bog blueberry (Vaccinium uligonosum). Dwarf shrubs such as Arctic willow (Salix arctica) occur throughout tundra biome except in coldest parts of High Arctic. Tall stands are restricted to warmer parts of Low Arctic, where typically found on floodplains (e.g., feltleaf willow Salix alaxensis) and mesic slopes (e.g., Siberian alder Alnus viridis ssp. fruticosa).
Evergreen shrubs 0–20 0.01–10 Widespread dwarf shrubs, except in High Arctic. Common species include entireleaf mountain-avens (Dryas integrifolia), mountain heather (Cassiope tetragona), lingonberry (Vaccinium vitis-idaea), and Labrador tea (Ledum decumbens).
Deciduous trees 150–1,000 1–25 The deciduous conifer, larch (Larix spp.), is the dominant tree in Siberian taiga-tundra ecotones. Poplar (Populus balsamifera) can occur on Low Arctic floodplains and south-facing slopes. Trees are typically widely spaced. Conifers typically have columnar growth form with small canopies; broadleaf trees often have larger canopies.
Evergreen trees 150–1,000 1–10 Evergreen conifers such as spruce (Picea spp.) are dominant in North American and European taiga-tundra ecotones.