Dryas octopetala, the mountain avens,
As a floral emblem, it is the official territorial flower of the Northwest Territories and the national flower of Iceland.
Description
The stems are woody, tortuous, with short, horizontal rooting branches. The
Leaf are glabrous above, densely white-
tomentose beneath. The
are produced on stalks long, and have eight creamy white petals – hence the specific epithet
octopetala.
The style is persistent on the
fruit with white feathery hairs, functioning as a wind-dispersal agent. The feathery hairs of the seed head first appear twisted together and glossy before spreading out to an expanded ball which the wind quickly disperses.
Distribution and habitat
Dryas octopetala has a widespread occurrence throughout mountainous areas where it is generally restricted to limestone outcrops. These include the entire
Arctic, as well as the mountains of
Scandinavia,
Iceland, the
Alps, the Carpathian Mountains, the
Balkans, the
Caucasus, and in isolated locations elsewhere. In
Great Britain, it occurs in the
Pennines of
Northern England, at two locations in the
Snowdonia region of
North Wales, and more widely in the Scottish Highlands. In
Ireland, it occurs on
The Burren and a few other sites. In
North America, it is found in
Alaska, most frequently on previously glaciated terrain, and through the
Canadian Rockies reaching as far south as
Colorado in the
Rocky Mountains.
It grows in dry localities where snow melts early, on gravel and rocky barrens, forming a distinct heath community on calcareous
.
Climatology
The
Younger Dryas,
Older Dryas and
Oldest Dryas are named after
Dryas octopetala, because of the great quantities of its
pollen found in cores dating from those times. During these cold spells,
Dryas octopetala was much more widely distributed than it is today, as large parts of the Northern Hemisphere that are now covered by
were replaced in the cold periods by
tundra.
Cultivation
D. octopetala is cultivated in
temperateness regions as
groundcover, or as an alpine or
rock garden plant. It has gained the Royal Horticultural Society's Award of Garden Merit.
The leaves are occasionally used as an herbal tea.
Gallery
Image:Weiße Silberwurz (Dryas octopetala) 2.jpg
Image:Dryas octopetala seed head.jpg|Seed head
Image:Weiße Silberwurz (Dryas octopetala) 1.jpg
Further reading
