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''Salix brachycarpa'' is a species of flowering plant in the willow family known by the common names barren-ground willow,〔Coladonato, Milo. 1993 (''Salix brachycarpa''. ) In: Fire Effects Information System, (). U.S. Department of Agriculture (USDA), Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.〕 small-fruit willow〔〔(''Salix brachycarpa''. ) ''Flora of North America''.〕 and shortfruit willow. It is native to North America, where it occurs throughout Alaska except for the Aleutian Islands and southeastern coastal region, in western and northern Canada, and in the contiguous United States in the Rocky Mountains south to Colorado.〔 A shrub growing up to 1.5 meters tall, ''S. brachycarpa'' is low in stature or sometimes prostrate. The stems are sometimes hairy and the smaller branchlets may be quite woolly. The leaves are also usually hairy, with woolly undersides. The species is dioecious, with male and female reproductive parts occurring on separate plants. The inflorescence is a catkin up to 5 centimeters long.〔〔 The plant produces tiny, downy seeds which are viable for just a few days but may germinate within 12 hours of hitting a suitable substrate.〔 ''S. brachycarpa'' grows in several types of habitat. It grows in coniferous forests and alpine habitat types, near rivers and streams, in bogs, muskegs, swamps, and moraines. It is common on floodplains, where it grows with other willow species and various shrubs. It can also be found on serpentine barrens, salt marshes, and salt flats. It easily colonizes wet places recently cleared of vegetation, such as gravel bars.〔 On the Alaska North Slope, sites that supported this and other low-growing willow species before being disturbed for construction of the Trans-Alaska Pipeline System were observed to have been recolonized by low-growing willows, including ''S. brachycarpa'', within four years after disturbance ceased. Natural regeneration of this and other low-growing willows was successful on moist riparian sites with silty soils, where they were mixed with the taller Alaska willow (''S. alaxensis''), and on dry sites with fine-textured soils. This willow provides food for moose in interior Alaska, and it has been planted to restore moose habitat in the Alaska North Slope.〔 It is also planted in revegetation efforts and as a windbreak.〔 Native Americans used parts of willows, including this species, for medicinal purposes, basket weaving, to make bows and arrows, and for building animal traps.〔 There are at least two recognized varieties of this species of willow: ''S. brachycarpa'' var. ''brachycarpa'' Nutt. is the typical variety, whereas ''S. brachycarpa'' var. ''niphoclada'' (Rydb.) Argus is considered the arctic variety.〔 There is also ''S. brachycarpa'' var. ''psammophila'' Raup, a variety endemic to the Lake Athabasca sand dunes in northern Saskatchewan, Canada.〔(''Salix brachycarpa'' Nuttall var. ''psammophila'' Raup. ) ''Flora of North America''.〕 A former subspecies, ''S. brachycarpa'' Nutt. subsp. ''niphoclada'' (Rydb.) Argus, is now synonymous with ''S. niphoclada'' Rydb., another Alaskan willow species that is also commonly referred to as barren-ground willow.〔 Of note, barren-ground willow is also the common name of a third but distinct species of willow found in Alaska, ''S. nummularia'' Andersson. ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Salix brachycarpa」の詳細全文を読む スポンサード リンク
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