The genus is situated in a monphyletic clade or sub-family known as the Arbutoideae, which is populated by taxa having bright fleshy berries with fibrous or bony endocarp. Evolution of the genus is relatively recent, with hybridization playing an important role, especially in non-crown sprouting taxa; however, convergent evolution patterns appear to complicate cladistic constructions for certain portions of the genus cladogram. In any case, fossil ancestors of the Arctostaphylos genus have been suggested to have occurred in the Middle Miocene, with modern species beginning to take shape in the Late Tertiary. Sands has further posited that in the earlier Tertiary a greater species diversity was present, influenced by influence of floristic influence of southwestern North America ancestors. This hypothesis also suggests that the present palette of California Arctostaphylos species became more depauperate upon arrival of a cooler drier climate in the Late Tertiary.These evolutionary views are coincident with other research that points to fire-dependent plant associations developing in the Late Miocene in California.
Earlier taxonomic treatments were governed by morphological methodology, most notably by Wells; however, more recent genome sequencing work by Boykin et al. has demonstrated the incongruence of purely morphological treatment with closely related species as determined by Internal Transcription Sequencing (ITS) methodology.
Arctous alpina (syn. Arctostaphylos alpina), the alpine bearberry, mountain bearberry or black bearberry, is a dwarf shrub in the heather family Ericaceae. The basionym of this species is Arbutus alpina L..
Arctous alpina is a procumbent shrub usually less than 6 inches (15 cm) high with a woody stem and straggling branches. The leaves are alternate and wither in the autumn but remain on the plant for another year. The leaves are stalked and are oval with serrated margins and a network of veins. They often turn red to scarlet in autumn. The flowers are in groups of two to five, white or pink and urn-shaped and about 3 to 5 mm (0.12 to 0.20 in) long. They have five sepals, five fused petals with five small projecting lobes, ten stamens and a single carpel. The fruits are spherical, 9 to 12 mm (0.35 to 0.47 in) long, initially green, then red and finally glossy black and succulent when ripe. This plant flowers in June.[2][3]
Arctous alpina has a circumpolar distribution. It is found at high latitudes, from Scotland east across Scandinavia, Russia, Alaska, Northern Canada and Greenland. Its southern limits in Europe are the Pyrenees and the Alps, in Asia, the Altay Mountains and Mongolia, and in North America, British Columbia in the west, and Maine and New Hampshire in the east.[4] Its natural habitat is moorland, dry forests with birch and pine and hummocks covered in moss at the edges of bogs.[3]
Arctous alpina forms a symbiotic relationship life with fungi which supply it with nutrients such as phosphorus. The berries are appreciated by birds.[3]
Arctous alpina (syn. Arctostaphylos alpina), the alpine bearberry, mountain bearberry or black bearberry, is a dwarf shrub in the heather family Ericaceae. The basionym of this species is Arbutus alpina L..
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