Cassiope lycopodioides
Cassiope lycopodioides is a plant species in the family Ericaceae, known by the common names clubmoss mountain-heather or Haida Gwaii mountain-heather. The species is native to northeast Asia and northwestern North America, where it grows on rocky slopes and crevices in arctic tundra and alpine tundra at elevations up to 2000 m.
Description
Cassiope lycopodioides is a perennial herb forming mats lying close to the ground. Leaves are narrow, up to 3 mm long, closely pressed against the stem. Curled hairs are present at the leaf tips, especially on younger leaves, and most populations display hyaline or scarious leaf margins. Flowers are white, campanulate, up to 20 mm across, and with a calyx of five fused sepals, often red or reddish green.Distribution
The distribution of Cassiope lycopodioides spans an arc of the northern Pacific Rim, extending from northeast Asia over to northwestern North America. In Asia, the species ranges from high elevations on Honshu and Hokkaido in Japan, north through coastal mountain ranges and tundra of the Russian Far East.In North America, the species is found across the Aleutian Islands into southern Alaska, coastal and interior British Columbia, and the U.S. State of Washington. Washington populations have been reported only from shaded alpine rock faces in King County and Snohomish County.
The specific epithet "lycopodioides" refers to the plant's superficial resemblance to some species of clubmoss ''.
Taxonomy
Cassiope lycopodioides subsp. cristapilosa, known only from the Haida Gwaii, is recognized as a distinct taxon by some authorities but not others. The distinction is based on morphological differences between Haida Gwaii plants and other populations, such as the lack of a hyaline margin to the leaf, and longer pedicels and corollas.Phylogenetic studies of Japan populations revealed genetic divergence between populations from central Honshu and populations from northern Honshu into Hokkaido; these are theorized to be two distinct colonizations of the species during different glaciation events during the Pleistocene, following a biogeographical pattern reflected by other alpine plant species in the archipelago.