Cornus canadensis
Encyclopedia
Cornus canadensis is a herbaceous
member of the Cornaceae
(dogwood
) family. It grows about 20–30 cm tall and bears tiny flower
s a few millimetres across that form an inflorescence
at the center of four white, petal-like bract
s 3–4 cm diameter.
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 800 times the acceleration that the Space Shuttle
does during liftoff. The Bunchberry has one of the fastest plant actions
found so far requiring a camera capable of shooting 10,000 frames per second to catch the action.
The fruits are edible with a mild flavour somewhat like apples. The large seeds within are somewhat hard and crunchy. 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.
While distinctive as a species itself, the 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. However, if Cornus is treated in a narrower sense, excluding this species, it can instead be classified as Chamaepericlymenum canadense or as Cornella canadensis.
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 hybridize by cross-pollination
, producing plants with intermediate characteristics.
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 mm long petioles and leaf blades that are obovate. The blades have entire margins and are 3.5 to 4.8 cm long and 1.5 to 2.5 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. Inflorescences are made up of compound terminal cymes, with large showy white bracts. The bracts are broadly ovate and 0.8 to 1.2 cm long and 0.5 to 1.1 cm wide, with 7 parallel running veins. The lower nodes on the stem have greatly reduced rudimentary leaves. In late spring to mid summer, white flowers are produced that are 2 mm in diameter with reflexed petals that are ovate-lanceolate in shape and 1.5 to 2 mm long. The calyx tube is obovate in shape and 1 mm long covered with densely pubescent hairs along with grayish white appressed trichomes. Stamens are very short, being 1 mm long. The anthers are yellowish white in color, narrowly ovoid in shape. The styles are 1 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. The fruits look like berries but are drupe
s. The drupes are green, globose round in shape, and turn bright red at maturity in late summer; each fruit is 5 mm in diameter and contains typically one or two ellipsoid-ovoid shaped stones.
Cornus canadensis is a mesophytic species that needs cool, moist soils. It is native to northern China
, far eastern Russia
, Japan
, and North America
in montane and boreal
coniferous 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.
Herbaceous
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
member of the Cornaceae
Cornaceae
Cornaceae is a cosmopolitan family of flowering plants in the order Cornales. It contains approximately 110 species, mostly trees and shrubs, which may be deciduous or evergreen. Members of this family usually have opposite or alternate simple leaves, four- or five-parted flowers clustered in...
(dogwood
Dogwood
The genus Cornus is a group of about 30-60 species of woody plants in the family Cornaceae, commonly known as dogwoods. Most dogwoods are deciduous trees or shrubs, but a few species are nearly herbaceous perennial subshrubs, and a few of the woody species are evergreen...
) family. It grows about 20–30 cm tall and bears tiny flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s a few millimetres across that form an inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
at the center of four white, petal-like bract
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s 3–4 cm diameter.
Petal
Petals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...
s that flip backward, releasing springy filaments that are cocked underneath the petals. The filaments snap upward flinging pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
out of containers hinged to the filaments. This motion takes place in less than half a millisecond and the pollen experiences 800 times the acceleration that the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
does during liftoff. The Bunchberry has one of the fastest plant actions
Rapid plant movement
Rapid plant movement encompasses movement in plant structures occurring over a very short period of time, usually under one second. For example, the Venus Flytrap closes its trap in about 100 milliseconds. The Dogwood Bunchberry's flower opens its petals and fires pollen in less than 0.5 milliseconds...
found so far requiring a camera capable of shooting 10,000 frames per second to catch the action.
The fruits are edible with a mild flavour somewhat like apples. The large seeds within are somewhat hard and crunchy. 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.
While distinctive as a species itself, the generic placement
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of these plants has differed in various botanical treatments. When the genus Cornus is taken broadly, as done here, this species is Cornus canadensis. However, if Cornus is treated in a narrower sense, excluding this species, it can instead be classified as Chamaepericlymenum canadense or as Cornella canadensis.
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 hybridize by cross-pollination
Pollination
Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
, producing plants with intermediate characteristics.
Description
Cornus canadensis is a slow-growing perennial herbaceous subshrub growing 10–20 cm tall, generally forming a carpet-like mat. The above-ground shoots rise from slender creeping rhizomes that are placed 2.5–7.5 cm deep in the soil, and form clonalCloning
Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...
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 mm long petioles and leaf blades that are obovate. The blades have entire margins and are 3.5 to 4.8 cm long and 1.5 to 2.5 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. Inflorescences are made up of compound terminal cymes, with large showy white bracts. The bracts are broadly ovate and 0.8 to 1.2 cm long and 0.5 to 1.1 cm wide, with 7 parallel running veins. The lower nodes on the stem have greatly reduced rudimentary leaves. In late spring to mid summer, white flowers are produced that are 2 mm in diameter with reflexed petals that are ovate-lanceolate in shape and 1.5 to 2 mm long. The calyx tube is obovate in shape and 1 mm long covered with densely pubescent hairs along with grayish white appressed trichomes. Stamens are very short, being 1 mm long. The anthers are yellowish white in color, narrowly ovoid in shape. The styles are 1 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. The fruits look like berries but are drupe
Drupe
In botany, a drupe is a fruit in which an outer fleshy part surrounds a shell of hardened endocarp with a seed inside. These fruits develop from a single carpel, and mostly from flowers with superior ovaries...
s. The drupes are green, globose round in shape, and turn bright red at maturity in late summer; each fruit is 5 mm in diameter and contains typically one or two ellipsoid-ovoid shaped stones.
Cornus canadensis is a mesophytic species that needs cool, moist soils. It is native to northern China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, far eastern Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, and North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
in montane and boreal
Boreal
Boreal may refer to*Boreal ecosystem**Boreal climate, the climate found in a region of boreal forests, and designated Dfc, Dwc or Dsc in the Köppen climate classification scheme.*boreal forest*Boreal forest of Canada*Boreal Bluet...
coniferous 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.
External links
- NCRS: USDA Plants Profile: Cornus canadensis
- Exploding Dogwood Flowers Williams College website describing the work of Joan Edwards and Dwight Whittaker, with videos and animations.
- Cornus canadensis holotype from Louis-Marie Herbarium (Laval University).
- Bunchberry, borealforest.org
- Bunchberry, Ontario's Wildflowers