Euphrasia hudsoniana (Hudson Bay Eyebright)
|Also known as:|
|Habitat:||part shade, sun; rocky cliffs and shoreline of Lake Superior|
|Bloom season:||July - August|
|Plant height:||3 to 14 inches|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Short, leafy spike at the top of the stem and ends of branching stems. The small, irregular flowers are ¼ inch or less with a 3-lobed lower petal and a double lobed or notched upper petal. Flowers are white to pale bluish or violet, with faint to prominent purple veins on both upper and lower petals and a bright yellow spot on the lower. Flower cluster opens progressively bottom to top, each flower attended by a leaf-like bract. Both the calyx and bracts have short, fine hairs (pubescent).
Leaves and stems:
Leaves are opposite, oval shaped, 1/6 to just under ½ inch long, have 3 to 5 blunt or sharply pointed teeth on each side, wedge shaped at the base, and stalkless. Short hairs cover the lower surface; the upper surface is hairy at least around the outer edges. Leaves may be closely packed along the stem or widely spaced. Stems are branched or unbranched, with short hairs throughout. Both stems and leaves can range in color from light green to dark purple.
A relic of the last ice age, today Hudson Bay Eyebright clings precariously to the cool rocky shorelines of Lake Superior's north shore. Listed by the DNR as a special concern species in 1984, remaining populations are put at risk from development, human foot traffic, warming climate, and non-native invasive species, in particular the introduction to North America of Tartary Eyebright (Euphrasia officianalis) that tolerates warmer gravelly soils and is rapidly spreading in inland habitats throughout the Arrowhead region. The two species look essentially identical to the casual observer, however E. hudsoniana has hairy leaves, whereas E. officinalis leaves are mostly hairless except for sparse hairs along the veins. Also, E. hudsoniana would never be found inland from the lake shore but E. officinalis is now becoming common along forest roads and recreational trails. Perhaps of greatest risk is hybridization, which would snuff out our unique North American evolutionary genotype. Of note is Euphrasia is not a well documented or well understood genus; there are references that claim E. nemorosa, another native, exists in Minnesota, but there are no records of it and the DNR does not include it in their official plant list, not even as an historical record. Likewise there are 3 recognized varieties of E. hudsoniana, 2 of which have been mentioned in various references as occurring in Minnesota, but only var. ramosior is currently recognized. The traits that distinguish these varieties is unknown (to us). The DNR notes that Euphrasia taxonomy and descriptions are under review at Flora of North America, which may require revising this account in the future.
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- Hudson Bay Eyebright in the grass
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- Hudson Bay Eyebright habitat
- a dense patch of Hudson Bay Eyebright
Photos by K. Chayka and Peter M. Dziuk taken at Temperance River State Park and Iona Beach SNA in Lake County, and at Artist's Point at Grand Marais, Cook County.
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