(bunchberry dogwood)
Select an option below for more information on this species
Photo of Cornus canadensis by Jacob Frank
|
Bunchberry dogwood is a common boreal herb, recognizable by its whorl of leaves framing a four-bracted white flower, often forming carpets in
deciduous and conifer forests. In fall, plants produce a cluster of berry-like orange-red
drupes. The species grows from creeping woody
rhizomes and often forms dense carpets, reaching heights of 8-15 cm. The leaves are
elliptic to
ovate in shape, with deeply impressed parallel veins. There are 4-7 in the upper whorl, with a pair of oppositely-arranged smaller leaves below them. Leaves are evergreen, turning dark red in fall. The flowers have four white 'petals',
ovate in shape, which are actually
bracts (modified leaves). The cluster in the center is actually made up of many highly reduced flowers. The
calyx is green, a fused tube, surrounding the tiny recurved white petals, with rounded lobes. Each flower has four
stamens, also white in color, and a dark purplish
carpel, the
style straight. The fruits are round, berry-like red
drupes, appetizing to birds but not humans. The similar but less common
Cornus suecica has several pairs of usually smaller opposite leaves along the upright stem, where
C. canadensis has only one pair below the large upper whorl of leaves.
Bunchberry begins flowering in mid-June, and produces fruits in August. The leaves are not
deciduous, and turn dark purple-red in fall to overwinter.
Cornus canadensis is
monoecious with bisexual flowers. The flowers of bunchberry are 'pollen catapults': pollen is launched vertically as the hinged
anthers spring outwards, releasing all the pollen they contain (
Mosquin 1985). This mechanism is triggered by touching an 'antenna' on the flower. The pollen reaches a height of 2.5 cm, letting it attach to insects or be carried away by the wind (
Edwards et al. 2005). Flowers are visited by bumblebees, solitary bees, beeflies, and syrphid flies (
Barrett and Helenurm 1987). This was the highest diversity of pollinators of all the species observed in their New Brunswick study. Bunchberry is highly self-incompatible: of 347 flowers self-fertilized by hand in Barrett and Helenurm's experiment, none set fruit (1987). The
drupes are dispersed mainly birds, and occasionally by small mammals (
Burger 1987). Seeds germinate best with a period of cold stratification (
Flessner and Trindle 2003). This species also has extensive clonal growth from its
rhizomes.
The fruits are edible to humans, but flavorless. The Yup'ik sometimes use it in akutaq ('Eskimo icecream'), mixed with other berries, but it is not preferred (Jernigan et al. 2015). The dwarf dogwoods, aka 'Bunchberries', were used by the Dena'ina for stomach troubles and eye problems as a tea brewed from the berrylike drupes (Andrews 1975 in Garibaldi 1999). The leaves of bunchberry have also been used for burns and cataracts by the Tlingit (de Laguna 1972 in Garibaldi 1999) and cuts by the Alutiiq (Wennekens 1985 in Garibaldi 1999). The berries are commonly eaten by birds and invertebrates (Burger 1987).
Disclaimer for Known Uses.
Cornus canadensis is an incompletely circumpolar species (amphi-Pacific) occurring across the northern hemisphere with large gaps, and absent from Europe. Cornus canadensis is broadly distributed in North America through boreal and northern temperate forests. Cornus canadensis occurs in all Canadian provinces and territories, and reaches the northeastern and Great Lakes states, barely reaching northern Virginia. In the western United States, it has small disjunct populations scattered through the Rockies. This species is abundant in central, southcentral and southeast Alaska, with some localities known from southwest and the southern edge of the Brooks Range. In Denali, Cornus canadensis occurs frequently across the boreal and subalpine areas of the Park, both north and south of the Alaska Range crest.
Details are shown in the Plots & Charts found at right, depicting recent Denali data.
Bunchberry is a low elevation species, found abundantly throughout the Park. It reaches the highest levels of cover at elevations of 300-500 meters, though it has been found from 83 to 1154 m in Denali. This species is most likely to occur in sites under 300 m, where it occurs in nearly 30% of plots. This species is more common on south-facing slopes. It is less common on slopes less than 4 degrees of incline, but is equally common on other angles.
Details are shown in the Plots & Charts found at right. For more on how to interpret these figures, visit Understanding Data Presented.
Specimens in the Alaska Range have been found on gravelly areas or in meadows.
Moist to somewhat dry sites.
