View source for Cornus canadensis

{{Speciesbox
|image = CanadianDogwoodGrowingTrailSide cropped.jpg
|image_caption = Growing at [[Elfin Lakes]], British Columbia
|status = G5
|status_system = TNC
|status_ref = <ref name=natureserve>{{Cite web
  | publisher =NatureServe
  | title = Cornus Canadensis
  | work = NatureServe Explorer
  | url = http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Cornus+canadensis+
  | accessdate = 2018-04-01}}</ref>
|genus = Cornus
|parent = Cornus subg. Arctocrania
|species = canadensis
|authority = [[Carl Linnaeus|L.]]
}}

'''''Cornus canadensis''''' ('''Canadian dwarf cornel''', '''Canadian bunchberry''', '''quatre-temps''', '''crackerberry''', '''creeping dogwood''') is a [[species]] of [[flowering plant]] in the [[Cornaceae]] (dogwood) [[family (biology)|family]], [[native plant|native]] to eastern Asia (Japan, [[Korea]], northeastern China ([[Jilin]] Province) and the [[Russian Far East]]), the northern United States, [[Colorado]], [[New Mexico]], Canada and [[Greenland]].<ref>{{cite book|title=RHS A-Z encyclopedia of garden plants|year=2008|publisher=Dorling Kindersley|location=United Kingdom|isbn=1405332964|pages=1136}}</ref> Unlike its relatives, which are for the most part substantial trees and shrubs, ''C. canadensis'' is a creeping, [[rhizome|rhizomatous]] [[perennial plant|perennial]] growing to about {{convert|20|cm|0|abbr=on}} tall.

== Description ==
''Cornus canadensis'' is a slow-growing [[herbaceous plant|herbaceous]] sub[[shrub]] growing 10&ndash;20&nbsp;cm tall, generally forming a carpet-like mat. The above-ground shoots rise from slender creeping rhizomes that are placed 2.5&ndash;7.5&nbsp;cm deep in the soil, and form [[cloning|clonal]] colonies under trees. The vertically produced above-ground stems are slender and unbranched. The leaves are oppositely arranged on the stem, but are clustered with six leaves that often seem to be in a whorl because the internodes are compressed.  The leafy green leaves are produced near the terminal node and consist of two types: 2 larger and 4 smaller leaves. The smaller leaves develop from the axillary buds of the larger leaves. The shiny dark green leaves have 2 to 3&nbsp;mm long petioles and leaf blades that are obovate. The blades have entire margins and are 3.5 to 4.8&nbsp;cm long and 1.5 to 2.5&nbsp;cm wide, with 2 or 3 veins and cuneate shaped bases and abruptly acuminate apexes. In the fall, the leaves have red tinted veins and turn completely red.

===Flowers===
[[File:Bunchberry plants.jpg|thumb|Mature and immature flowers, [[Bonnechere Provincial Park]], [[Ontario]]
]]
In late spring to midsummer, white flowers are produced that are {{convert|2|mm|abbr=in|frac=32}} in diameter with reflexed [[petal]]s that are [[ovate]]-[[lanceolate]] in shape and {{convert|1|-|2|mm|abbr=in|frac=32}} long.<ref>{{eFloras|1|242443972|Cornus canadensis|first1=Zack E. |last1=Murrell |first2=Derick B. |last2=Poindexter |family=Cornaceae}}</ref> [[Inflorescence]]s are made up of compound terminal [[cyme (botany)|cyme]]s, with large showy white [[bract]]s that resemble petals. The bracts are green when immature. The bracts are broadly ovate and {{convert|0.8|to|1.2|cm|in|frac=16|abbr=in}} long and {{convert|0.5|to|1.1|cm|in|frac=32|abbr=in}} wide, with 7 parallel running veins. The lower nodes on the stem have greatly reduced rudimentary leaves.  The [[sepal|calyx]] tube is [[obovate]] in shape and 1&nbsp;mm long, covered with densely pubescent hairs along with grayish white [[appressed]] [[trichomes]].  [[Stamen]]s are very short, being 1&nbsp;mm long. The anthers are yellowish white in color, narrowly ovoid in shape. The styles are 1&nbsp;mm long and glabrous. Plants are for the most part self-sterile and dependent on pollinators for sexual reproduction. Pollinators include bumblebees, solitary bees, beeflies, and syrphid flies.<ref>Barrett, Spencer C.; Helenurm, Kaius. 1987. ''The reproductive biology of boreal forest herbs. I. Breeding systems and pollination''. Canadian Journal of Botany. 65: 2036-2046.</ref>  The fruits look like berries but are [[drupe]]s.

===Release of pollen===
Each flower has highly elastic [[petal]]s that flip backward, releasing springy filaments that are cocked underneath the petals. The filaments snap upward flinging [[pollen]] out of containers hinged to the filaments. This motion takes place in less than half a millisecond and the pollen experiences two to three thousand times the force of gravity.<ref>[https://pomona.academia.edu/DwightWhitaker/Papers/226812/Botany_A_Record-Breaking_Pollen_Catapult ''A record-breaking pollen catapult'' at Academia.edu]</ref>  The Bunchberry has one of the [[Rapid plant movement|fastest plant actions]] found so far requiring a camera capable of shooting 10,000 frames per second to catch the action.<ref>{{cite journal | vauthors=Edwards J, Whitaker D, Klionsky S, Laskowski MJ | title=Botany: a record-breaking pollen catapult | journal=[[Nature (journal)|Nature]] | volume=435 | issue=7039 | year=2005 | pages=164 | pmid=15889081 | doi=10.1038/435164a}}</ref>

===Fruit===
[[File:Bunchberry Immature flowers.jpg|thumb|Immature flowers]]
[[File:Ccanadensis.jpg|thumb|Fruit]]
The drupes are green, globose in shape, turning bright red at maturity in late summer; each fruit is 5&nbsp;mm in diameter and contains typically one or two ellipsoid-ovoid shaped stones. The fruits are edible with a mild flavour somewhat like apples. The large seeds within are somewhat hard and crunchy.

==Taxonomy==
While distinctive as a species itself, the [[genus|generic placement]] of these plants has differed in various botanical treatments. When the genus ''[[Cornus]]'' is taken broadly, as done here, this species is ''Cornus canadensis'', and is included in the subgenus ''Arctocrania''.<ref>{{eFloras|1|316357|Cornus subg. Arctocrania|first1=Zack E. |last1=Murrell |first2=Derick B. |last2=Poindexter |family=Cornaceae}}</ref> However, if ''Cornus'' is treated in a narrower sense, excluding this species, it can instead be classified as ''Chamaepericlymenum canadense'' or as ''Cornella canadensis.''<ref>Eyde, R. H. 1987. ''The case for keeping Cornus in the broad Linnaean sense.'' Systematic Botany. 12(4): 505-518.</ref><ref>Eyde, Richard H. 1988. ''Comprehending Cornus: puzzles and progress in the systematics of the dogwoods''. Botanical Review. 54(3): 233-351.</ref>

Where bunchberry, a forest species, and ''[[Cornus suecica]]'', a bog species, grow near each other in their overlapping ranges in Alaska, Labrador, and Greenland, they can [[Hybrid (biology)|hybridize]] by [[pollination|cross-pollination]], producing plants with intermediate characteristics.<ref>Neiland, Bonita J. 1971. ''The forest-bog complex of southeast Alaska''. Vegetatio. 22: 1-64.</ref><ref>Murrell, Zack E. 1994. ''Dwarf dogwoods: Intermediacy and the morphological landscape.'' Systematic Botany 19: 539-556.</ref>

==Habitat==
''Cornus canadensis'' is a [[mesophytic]] species that needs cool, moist soils.  It inhabits montane and [[boreal forest of Canada|boreal]] [[pinophyta|conifer]]ous forests, where it is found growing along the margins of moist woods, on old tree stumps, in mossy areas, and amongst other open and moist habitats.

==Ecology==
Birds are the main dispersal agents of the seeds, consuming the fruit during their fall migration. In Alaska, bunchberry is an important forage plant for mule deer, black-tailed deer and moose, which consume it throughout the growing season.<ref>Hanley, Thomas A.; Cates, Rex G.; Van Horne, Beatrice; McKendrick, Jay D. 1987. Forest stand-age related differences in apparent nutritional quality of forage for deer in southeastern Alaska. In: Provenza, Frederick D.; Flinders, Jerran T.; McArthur, E. Durant, compilers. Proceedings--symposium on plant-herbivore interactions; 1985 August 7–9; Snowbird, UT. Gen. Tech. Rep. INT-222. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 9-17.</ref>

==Symbolism==
[[Claire Waight Keller]] included the plant to represent Canada in [[Meghan Markle|Meghan Markle's]] [[Wedding of Prince Harry and Meghan Markle|wedding]] veil, which included the distinctive flora of each [[Commonwealth of Nations|Commonwealth]] country.<ref>https://www.royal.uk/wedding-dress-bridesmaids%E2%80%99-dresses-and-page-boys-uniforms</ref>

==References==
<references />

==External links==
{{Commons category}}
*[http://www.williams.edu/Biology/explodingflower/ Exploding Dogwood Flowers] Williams College website describing the work of Joan Edwards and Dwight Whittaker, with videos and animations.
*[https://web.archive.org/web/20090729210956/http://www.herbier.ulaval.ca/specimens_types/template.php?pid=0006389 ''Cornus canadensis'' holotype] from Louis-Marie Herbarium ([[Laval University]]).
*[http://www.borealforest.org/herbs/herb11.htm Bunchberry], borealforest.org
*[http://ontariowildflowers.com/main/species.php?id=35 Bunchberry], Ontario's Wildflowers
{{Taxonbar|from=Q1420828}}

[[Category:Cornus|canadensis]]
[[Category:Flora of Canada]]
[[Category:Flora of Greenland]]
[[Category:Flora of the Northwestern United States]]
[[Category:Flora of the Northeastern United States]]
[[Category:Flora of the Appalachian Mountains]]
[[Category:Flora of Alaska]]
[[Category:Flora of Ontario]]
[[Category:Flora of West Virginia]]
[[Category:Flora of New Mexico]]
[[Category:Flora of China]]
[[Category:Flora of Virginia]]
[[Category:Flora of Japan]]
[[Category:Flora of Russia]]
[[Category:Flora of Colorado]]
[[Category:Flora of Jilin]]
[[Category:Flora of Korea]]
[[Category:Plants described in 1753]]