Abstract
Five field seasons have been spent in the Jackson Hole region. Teton County, as a political boundary, does not exactly define the natural floristic area. Since there is little or no endemism among the plants of Teton County, other criteria must be sought for defining the boundaries of the Teton County flora as a unit. To do this, it seems most satisfactory to fall back upon geology and take the area which was so affected by the events of the Pleistocene that they are still reflected in the patterns of the vegetation. Project Number 85.