Alaskan bunchberry
Cornaceae (Dogwood family)
Introduction to Vascular Plants
Introduction
Cornus unalaschkensis (Alaskan bunchberry) is a small dogwood species that is found along the Pacific Coast in North America (BC, AK, CA, ID, OR, WA) (USDA 2010). In British Columbia, it is primarily coastal in distribution. Plants in the Fraser Valley are considered to be this species. Alaskan bunchberry flowers in our region from June through August at higher elevations.
Species description: Perennial herb. Stem erect, < 20 cm. Leaves 2-8 cm, elliptic to ovate, glabrous or hairy, in a whorl of 4-6 below inflorescence, plus a pair of small ones near the middle of the stem. Inflorescence head-like, 2-4 cm wide, surrounded by 4 conspicuous white, petal-like bracts, 0.8-2.0 mm. Sepals 0.4 mm, petals 1.5 mm, white with purple tips. Fruit a drupe, spherical, 6-8 mm, red, stone smooth. Habitat moist forest and bogs. Commonly confused with C. canadensis, even in the scientific literature, this is a distinct species. It is an allopolyploid, derived by chromosome doubling in a hybrid of C. canadensis and C. suecica, and apparently originated before the last glaciation. Cornus canadensis differs in having white petals, and the pair of stem leaves are bract-like, < 1 cm long. This is an excellent ornamental. Note Author: Fred Ganders, 2010 |
Status Information
Synonyms
Synonyms and Alternate Names:
Chamaepericlymenum unalaschkense (Ledeb.) Rydb.
Similar Species
There are three species of bunchberry in British Columbia: Cornus canadensis, Cornus suecica, and Cornus unalaschkensis. All three species are very similar in appearance, and are not easy to separate, often requiring microscopic work. However there are some distinguishing characteristics that are readily visible. Griffith and Ganders (1983) provides the following description of the three species:
"[Cornus canadensis] has four to six leaves at the top of its stem and greenish-white petals (not the showy white bracts, but the tiny petals inside the bracts).....[Cornus suecica] has three to six more or less equal pairs of leaves along it's short stem....the petals are purple or at least partially purple......[Cornus unalaschkensis] has flowers like those of [Cornus suecica], but has whorls of leaves like those of [Cornus canadensis]." |
Taxonomic Notes
The geographical range of western bunchberry is almost completely separate from its two parent species, being south of that of northern bunchberry and west and south of that of Canada bunchberry. However, the ranges of northern bunchberry and Canada bunchberry overlap north of the Alaska panhandle, and hybrids between these two species have been found there. These hybrids look like western bunchberry, but they are diploid (no chromosome doubling having occurred) and mostly sterile; only about half their pollen is viable, and they rarely set seed. Current hybridization between the two parent species takes place outside the present range of western bunchberry and apparently has not yet led to the production of allotetraploids there. The hybridization and allopolyploidy that produced western bunchberry took place sometime before the last glaciation, and the tetraploids survived farther south than the parent species and subsequently recolonized an area where the parents had not occurred or had been eliminated.
Source: Extracted from Wildflower Genetics, A Field Guide for British Columbia and the Pacific Northwest (1983), with permission. |
References
Griffiths, Anthony J. F. and Fred R. Ganders. 1983. Wildflower Genetics: A Field Guide for British Columbia and the Pacific Northwest. Flight Press, Vancouver, BC.