Heath Family — Ericaceae
|A close-up of Lapland rosebay, Rhododendron lapponicum.|
This family of dwarf, evergreen shrubs is diverse and ecologically significant, providing food for many birds, mammals, and humans. Approximately ten genera are represented in the Canadian Arctic and these are placed into three groups: Group I – plants with showy, upward-facing flowers; Group II – plants with bell-shaped flowers; and Group III – plants with juicy berries.
Group I: the genera Loiseleuria, Ledum, and Rhododendron.
Alpine azalea, Loiseleuria procumbens, is a low, woody plant, which grows pressed close to the ground. Its shiny, leathery leaves are very small, less than 4 mm long, and possess a waxy coating, which helps to prevent water loss. Each flower has five pink petals arranged in a star-shaped pattern.
The Labrador teas – marsh Labrador tea, Ledum decumbens, and bog Labrador tea, L. groenlandicum – are also low-lying shrubs and bear narrow, alternate evergreen leaves whose margins are rolled and densely-haired underneath. When crushed, these plants are strongly aromatic, a trait that can be used to identify them once the flowers fade. In full bloom, however, their clustered white flowers provide an explosion of colour across the tundra.
Lapland rosebay, Rhododendron lapponicum, blooms early in the arctic summer, sprinkling gravelly areas with bursts of pinkish-purple flowers. Rosebay branches, as well as the undersides of its oval-shaped, leathery leaves, are covered in brown scales. Leaves are clustered at the ends of the branches; the fragrant flowers are also clustered in groups of four to eight. An unusual aspect of this woody shrub is its choice of soil type. All other members of the genus Rhododendron occur on acidic soils, whereas R. lapponicum thrives on limestone soils, which are basic.
To learn about another member of this group, the White Heather (Cassiope tetragona), please click here.
Group II: the genera Cassiope, Andromeda, Phyllodoce, and Chamaedaphne.
Moss heather, Cassiope hypnoides, gains its name from its moss-like, needle-shaped leaves that overlap each other like tiles on a roof. Its bell-shaped flowers are small and white; the calyx, wine-red. This plant commonly grows in sheltered, rocky places, along brooks and lake shores, where the snow remains late.
Bog rosemary, Andromeda polifolia, is an attractive evergreen shrub, whose leaves are narrow and deeply grooved, with whitish undersides and the edges turned in. Its flowers are shaped more like an urn than a bell, and possess five pink petals that join five darker pink sepals to form the urn. The distinguishing feature of the bog rosemary is its pinkish-red fruits, which resemble tiny apples sitting on pedestals.
Like the moss heather, mountain heather, Phyllodoce coerulea, has alternate, needle-shaped, evergreen leaves. This plant, common on southern Baffin Island, bears purple-pink flowers with scattered white hairs, and a hairy, reddish-purple calyx. It grows in turfy places where the snow remains late in the summer.
The leather leaf, Chamaedaphne calyculata, thrives in bogs, muskeg, and along lake margins, just north of the treeline. Its leaves are alternate and evergreen, while its flowers are white and grow along one side of the stem.
Group III: the genera Arctostaphylos, Oxycoccus, and Vaccinium.
The bearberries, Arctostaphylos spp., form mats that spread over large areas and often grow amongst blueberry and cranberry. To learn about the bearberry, click here.