In several respects the flora of the Tetons is unique. The high
mountains have constituted a plant-migration barrier which many forms
could not cross; hence the range limit of a number of species is found
here. Representatives from north, south, east, and west are in the
region, this being the limit, in many instances, of their distribution.
There are a number of plants typical of the central Rockies and a few
known only to this range. Four life zones are recognized within the
park, all occurring within a distance of less than 15 miles.
[Illustration: _A part of the Jackson Hole Elk herd._]
The flowering period begins in the park as soon as the ridges and flats
are free of snow in May, and it continues until about August 15 in the
Arctic-Alpine Zone. Hence, plants of at least one zone and usually of
several may be seen blooming at any time in the spring or summer.
The evergreen trees (of which the lodgepole pine, limber pine, whitebark
pine, Engelmann spruce, and alpine fir are most common) form an
appropriate frame for the majestic Teton peaks and are reflected in the
lakes which they encircle.