Plants of the "Driftless Area"

In 1823, W. H. Keating, a geologist from the University of Pennsylvania, traveled overland from Chicago to Prairie du Chien, Wisconsin, and then continued his journey up the Mississippi River to northern Minnesota. When crossing from northern Illinois into southwestern Wisconsin he noted the absence of the granite boulders that we now know were brought to glaciated areas by continental ice sheets. In a narrative of this trip, published in 1824, he commented upon this and upon his observation of the resumption of erratics as he passed the Lake St. Croix region in Minnesota. Thus, Keating was the first geologist to visit the "Driftless Area" and clearly recognize its contrast with the glaciated surrounding area. Today the "Driftless Area" is known the world over because it is completely surrounded by glaciated territory and apparently was not covered by continental glaciation during the Pleistocene epoch. Within the belts covered by contiental ice sheets of northeastern North America and northwestern Europe there is no similar region of substantial size which was left bare of glacial ice. It is important to point out, however, that this area, which today is an island in the glacial drift, was never an island in the ice during Pleistocene glaciation. The various glacial lobes advanced southward at different times and speeds thus never completely isolating the "Driftless Area" from the non-glaciated areas of central and southern United States... This study of the "Driftless Area" was begun early in 1956. As work progressed, the following objectives became clear: a) to determine the species of vascular plants that grow or have grown spontaneously in the area, b) to determine the frequency and geographic distribution of these species within the area, c) to determine the ecological preferences of these species, and d) to investigate the relationship between the flora the the Pleistocene history of the area... The entire first set of these vouchers is deposited at the herbarium of The University of Iowa. Other sets are being distributed to various herbaria.