Empetrum nigrum, crowberry,[1] black crowberry, or, in western Alaska, blackberry, is a flowering plant species in the heather family Ericaceae with a near circumboreal distribution in the Northern Hemisphere. It is usually dioecious, but there is a bisexual tetraploid subspecies, Empetrum nigrum subsp. hermaphroditum, which occurs in more northerly locations and at higher altitude.[2] [3]
Empetrum nigrum is a low growing, evergreen shrub with a creeping habit.[4] The leaves are NaNmm long, arranged alternately along the stem. The stems are red when young and then fade to brown. It blooms between May and June. The flowers are small and not very noticeable,[4] with greenish-pink sepals that turn reddish purple.[5] The round fruits are drupes, NaNmm wide, usually black or purplish-black but occasionally red.[6]
The metabolism and photosynthetic parameters of Empetrum can be altered in winter-warming experiments.[7]
The species has a near circumboreal distribution in the Northern Hemisphere. It is also native in the Falkland Islands.[10]
Evolutionary biologists have explained the striking geographic distribution of crowberries as a result of long-distance migratory birds dispersing seeds from one pole to the other.[11]
Empetrum nigrum grows in acidic soils in shady, moist areas.
The moth species Glacies coracina, Zygaena exulans, and Hadula melanopa feed on the plant.
The fruit is edible and can be dried.[12] However, it has an acidic taste and can cause headaches.[13] It is abundant in Scandinavia and treasured for its ability to make liqueur, wine, juice, or jelly. In subarctic areas, the plant has been a vital addition to the diet of the Inuit and the Sami. The Dena'ina (Tanaina) harvest it for food, sometimes storing in quantity for winter, sometimes mixed with lard or oil.
The species can also be grown as a ground cover,[14] or as an ornamental plant in rock gardens, notably the yellow-foliaged cultivar 'Lucia'. The fruit is high in anthocyanin pigment and can be used to make a natural dye.
The Scottish Highlands Clan Maclean's badge is believed to be E. nigrum; cuttings of it would be raised on standards to denote clan identity and allegiance.