He former are pure associations, and are well illustrated by a mther moor, where Calluna vulgaris is the dominant plant.
A local aggrettion of a species other than the dominant one in an associion brings about a plant society; for example, societies of Ericd etralix, of Scirpus caespitosus, of Molinia coerulea, of Carex irta, of Narthecium ossifra gum, and others may occur within i association of Calluna vulgaris.
Some such species are Blechnum boreale, Aira flexuosa, Calluna vulgaris, Vaccinium, Myrlillus, Rubus, Chamaemorus, Empetrum nigrum, Drosera spp. Some, at least, of these species possess mycorhiza in their roots, and are perhaps unable to live in soils where such organisms are absent.
The former is poor in Cruciferae, Caryophyllaceae, Umbelliferae, Primulaceae and Labiatae; but for the occurrence of Calluna in Newfoundland it would have no heaths.
Professor Macoun gives us a few notable species - Calluna vulgaris, Salisb., Alchemilla vulgaris, L., Rhododendron maximum, L., Ilex glabia, Gray, Hudsonia ericoides, L., Gaylussacia dumosa, F.
Heath (Erica tetralix) and ling (Calluna vulgaris) cover all the waste sandy regions in the eastern division of the country.