Harrimanella is a small genus of flowering plants in the heath family Ericaceae, order Ericales. It comprises two accepted species of dwarf, cold-hardy perennials native to arctic and subarctic regions of the Northern Hemisphere.
Plants in this genus form dense, moss-like cushions typically no more than 5 centimetres (2 inches) tall, with prostrate stems and ascending shoot tips. The leaves are tiny and scale-like, closely resembling those of mosses, which accounts for the common names "moss bell heather" and "moss heather" applied to the best-known species, Harrimanella hypnoides. Flowers are borne singly on short reddish pedicels and are bell-shaped, white, with five fused petals and five sepals — a form characteristic of many heathland genera. The fruit is an erect capsule.
H. hypnoides was originally described as Cassiope hypnoides by Carl Linnaeus in his Flora Lapponica (1737). The genus Harrimanella was later segregated from Cassiope by Frederick Vernon Coville, and the new combination is the accepted name in the Integrated Taxonomic Information System (ITIS). The second species, Harrimanella stelleriana, ranges across the North Pacific and is also accepted within the genus.
Etymology
The genus name Harrimanella honours the Harriman Alaska Expedition of 1899. The specific epithet of the type species, hypnoides, derives from the Greek meaning "resembling Hypnum" — a genus of mosses — reflecting the plant's unusually moss-like foliage.
Distribution
Harrimanella species occur in arctic and subarctic habitats across the Northern Hemisphere. H. hypnoides grows on rock crevices and ledges in the Canadian arctic, Quebec, the northeastern United States, Greenland, Iceland, Svalbard, arctic Russia (including the Ural Mountains), and the mountains of Norway, Sweden, and Finland. H. stelleriana has a North Pacific distribution.
Ecology
Plants grow in exposed arctic and alpine rock crevices, where their low-cushion growth form reduces wind exposure and conserves heat. The moss-like habit allows the genus to colonise nutrient-poor, rocky substrates typical of tundra and high-mountain environments.
Taxonomy Notes
Harrimanella was segregated from the closely related genus Cassiope (also Ericaceae). The type species was originally described by Linnaeus as Cassiope hypnoides in Flora Lapponica (1737). Coville later erected Harrimanella to accommodate the most moss-like members of that alliance. GBIF places the genus in family Ericaceae, order Ericales, class Magnoliopsida.
