|Title||Black crowberry in the Lake Superior region|
|Publication Type||Journal Article|
|Year of Publication||1964|
|Authors||Soper JH, Voss EG|
Attention has been focussed recently on the distribution and affinities of some of the distinctive shoreline plants of the Great Lakes region (Guire & Voss, 1963). A factor responsible for part of the continuing current interest in the phytogeography of this area has been the completion in September, 1960 of the Lake Superior portion of the Trans-Canada Highway (Soper, 1963). The subsequent increase in botanical exploration has resulted in the appearance in several herbaria of collections from areas around the north shore of Lake Superior which previously had been difficult to reach. Among the shoreline species, some are truly arctic-alpine and their occurrences in the Great Lakes region are usually limited to the north shore of Lake Superior, with perhaps an additional isolated station on the Keweenaw Peninsula of the south shore. The absence of collections and reports for such species from the shores of the other Great Lakes suggests that only Lake Superior has a large enough body of cold water with shoreline habitats sufficiently similar in soils, exposures, and climate to those in which the species in question thrive in the arctic. In some cases, one site may contain a whole community of northern species (Soper & Maycock, 1963). Few truly northern species are found as far south as the sandy southeast shores of Lake Superior but one noteworthy example in this category is the Black Crowberry (Empetrum nigrum L.).