''Dryas integrifolia'' is a species of flowering plant in the rose family known by the common names arctic avens,Louis-Marie, P. ND. Flore-Manuel de la Province de Québec, Canada (3e édition). Cooperative Harpell's Press, Gardenvale, PQ. entireleaf mountain-avens, white mountain-avens, northern white mountain avens,''Dryas integrifolia''.
NatureServe. and mountain avens.Aiken, S.G., et al. 2007

NRC Research Press, National Research Council of Canada, Ottawa. It is native to northern parts of North America, where it occurs from Alaska across Canada to Greenland. It is a common species of the Arctic and it is probably the most common flowering plant on some of the western Arctic islands. This plant is a

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

, often a

dwarf shrub A subshrub (Latin ''suffrutex'') or dwarf shrub is a short shrub, and is a woody plant. Prostrate shrub is a related term. "Subshrub" is often used interchangeably with "bush".Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Der ...

. It forms a prostrate mat up to to tall, the stems branching horizontally along the ground. The leaves are borne on stipulate petioles that are covered in long, silky or woolly hairs. The leaf blades are linear to lance-shaped and measure up to long. The blades have smooth upper surfaces and densely haired undersides. The flowering stem (

peduncle Peduncle may refer to: *Peduncle (botany), a stalk supporting an inflorescence, which is the part of the shoot of seed plants where flowers are formed *Peduncle (anatomy), a stem, through which a mass of tissue is attached to a body **Peduncle (art ...

) has no leaves on it but is covered in long woolly hairs. It bears a single flower with up to 11 obovate petals which are usually white but may be shades of yellow or cream. In the middle are many

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s tipped with yellow anthers. The styles start small and enlarge as the attached fruits mature, becoming up to long and sporting a plumelike coat of long, fluffy hairs. These plumes tangle together, and clumps of fruits fall away from the plant to be borne away on the wind.Au, R. (2006)
Dendroecology of the dwarf shrub ''Dryas integrifolia'' near Churchill, Manitoba (Thesis).
University of Winnipeg. The fruit is an

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

. Some flowers exhibit

heliotropism Heliotropism, a form of tropism, is the diurnal or seasonal motion of plant parts (flowers or leaves) in response to the direction of the Sun. The habit of some plants to move in the direction of the Sun, a form of tropism, was already known by t ...

, changing orientation to follow the sun. Others grow toward the position of the sun at noon.Krannitz, P. G. (1996)
Reproductive ecology of ''Dryas integrifolia'' in the high Arctic semi-desert.
''Canadian Journal of Botany''. 74:9 1451-60. As the flower faces the sun it provides a resting spot for a variety of insects, being slightly warmer than surrounding surfaces.Wilmer, P., et al. (2005). ''Environmental Physiology of Animals''. 2nd Ed. Blackwell Publishing. Malden, MA. pg 651. Additionally, character expression of the various adjacent floral organs has been seen to demonstrate

atavistic In biology, an atavism is a modification of a biological structure whereby an ancestral genetic trait reappears after having been lost through evolutionary change in previous generations. Atavisms can occur in several ways; one of which is when ...

character convergence, such that petals may bear the yellow mark of

anthers The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

, or a greenish midrib, as

sepals A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

do.Hart, G. T. 1988. Dryas integrifolia and its habitat diversity in the Canadian High and Low Arctic (Thesis). University of Toronto, Ontario. xix, 207. This species is actinorhizal, able to live in

symbiosis Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

with nitrogen-fixing bacteria. It can also form a symbiosis with the mushroom '' Hebeloma cylindrosporum'' via an

ectomycorrhiza An ectomycorrhiza (from Greek ἐκτός ', "outside", μύκης ', "fungus", and ῥίζα ', "root"; pl. ectomycorrhizas or ectomycorrhizae, abbreviated EcM) is a form of symbiotic relationship that occurs between a fungal symbiont, or mycobi ...

.Melville, L. H., et al. (1987)
Ontogeny of early stages of ectomycorrhizae synthesized between ''Dryas integrifolia'' and ''Hebeloma cylindrosporum''.
''Botanical Gazette'' 148:3 332-41. This plant is common in many Arctic regions, growing in several types of cold, wet habitat. It can be found in tundra, meadows, river valleys, and scree slopes. It anchors well in rocky and gravelly substrates, and it thrives in soils with low organic content. It is a pioneer species in rough terrain. It likely colonized wide areas of the Arctic as ice sheets receded.Tremblay, N. O. and D. J. Schoen. (1999)
Molecular phylogeography of ''Dryas integrifolia'': glacial refugia and postglacial recolonization.
''Molecular Ecology'' 8 7 1187–98. This species dominates several Arctic habitat types, being the first plant to take hold in the scoured substrate and becoming the most abundant species in the area. It dominates a dwarf heath plant community along with sedges such as '' Carex rupestris'' in Montana.''Dryas integrifolia'' - ''Carex'' spp. Dwarf Shrub Herbaceous Vegetation.
Montana Natural Heritage Program. In parts of northern Alaska it codominates bare, cryoturbated soils with the

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.Ochrolechia frigida ''Ochrolechia frigida'' is a species of lichen belonging to the family Ochrolechiaceae. It was first formally described by Olof Peter Swartz in 1781, as ''Lichen frigidus''. Bernt Arne Lynge transferred it to '' Ochrolechia'' in 1928. It is a ...

'',8. ''Dryas integrifolia''-''Ochrolechia frigida''.
Toolik Arctic Geobotanical Atlas. Alaska Geobotany Center. and moist coastal flats with ''

Carex aquatilis ''Carex aquatilis'' is a species of Carex, sedge known as water sedge and leafy tussock sedge. It has a Circumboreal Region, circumboreal distribution, occurring throughout the northern reaches of the Northern Hemisphere. It grows in many types o ...

'', a sedge.9. ''Carex aquatilis''-''Dryas integrifolia''.
Toolik Arctic Geobotanical Atlas. Alaska Geobotany Center. The plant's ability to colonize denuded Arctic landscapes makes it a useful tool in revegetation efforts, particularly in habitat altered by mining. Once the plant takes hold, its dense, matlike form tends to accumulate organic matter. Increasing the organic cover in a barren mining zone is considered an important goal in revegetation efforts.Firlotte, N. and R. J. Staniforth. (1995)
Strategies for revegetation of disturbed gravel areas in climate stressed subarctic environments with special reference to Churchill, Manitoba, Canada: A literature review.
''Climate Research'' 5 49-52. The Inuit have many names for the species, including ''malikkaat'', ''isuqtannguat'', ''isurramuat'', and ''piluit''. They monitored the status of the plant in order to track the seasons.

References

{{Taxonbar, from=Q3040181 Dryadoideae Taxa named by Martin Vahl Flora of Greenland