ually comes to form a larger proportion of the whole until at 9,000 feet and upward it constitutes practically an unbroken forest to the exclusion of other species. At timber line it becomes scattering, dwarfed and depressed, spreading out like a huge mat under the enormous pressure of the winter snows.

Practically the same conditions prevail in the Wind River Mountains, and probably, though I cannot speak from observation, in the Big Horn Mountains.

Of the fruticose and herbaceous vegetation I need not speak here, although the summits of these ranges yield many beautiful and strictly alpine forms. These all receive comment in their proper place in the list, so space may not be consumed for that purpose here.

THE TREES OF THE STATE.

A list of the trees of the state is indeed very short and were those on the border line between trees and shrubs excluded in would be shorter yet by a third.

Rocky Mountain Yellow Pine (Pinus ponderosa scopulorum).
Rocky Mountain White Pine (Pinus flexilis).

Lodge Pole Pine (Pinus Murrayana).
Engelmann's Spruce (Picea Engelmanni).
Blue Spruce (Picea pungens).

Douglas Spruce (Pseudotsuga Douglasii).
Virginia Juniper (Juniperus Virginiana).
Black Cottonwood (Populus angustifolia).
Rydberg's Cottonwood (Populus acuminata).
Quaking Asp, Aspen (Populus tremuloides).
Willow (Salix longifolia).

Willow (Salix flavescens).

Willow (Salix amygdaloides).
Willow (Salix lasiandra).

Green Ash (Fraxinus viridis).

Box Elder (Negundo aceroides).

Scrub Oak (Quercus undulata)
Wild Plum (Prunus Americana).
Wild Cherry (Prunus demissa).
Wild Cherry (Prunus Virginiana).
Hawthorn (Cratægus rivularis).
Hawthorn (Cratagus Douglasii).
Service Berry (Amelanchier alnifolia).
(Eleagnus argentea).

Buffalo Berry (Shepherdia argentea).
Black Birch (Betula occidentalis).
Black Alder (Alnus incana virescens).
Sage Brush (Artemisia tridentata).

In a few localities of the state occasional specimens of Sage Brush attain a remarkable size-small trees in fact —so that a man on horseback may ride erect underneath the branches.

Other species have been reported but until the specimens are at hand they will not be listed. The number of shrubby plants is so great that to list them separately would be to reprint a large part of the succeeding systematic list.

THE FLORAS OF THE PACIFIC AND THE ATLANTIC

SLOPES.

I have had no opportunity to compare the floras of the two regions except in so far as the plants on the western side of the Wind River range and those of Jackson's Hole and the Tetons, all of which are on the Pacific slope, may be compared with those on the eastern side of the Wind River Mountains and those of the south-eastern part of the state, which represent the Atlantic slope. Such examination has led to the conclusion that the continental divide, though dividing the waters, does not separate floras. The two regions have a far larger number

due mainly to the I am confirmed in given in Dr. J. M.

in common than they have of forms that are distinct. While my collection lists show much that is different, I firmly believe that the difference is scason in which each was collected. this by an examination of the lists Coulter's report on the Botany of the Hayden U. S. Geological Survey, 1872. These lists comprise those collected, 1. On both slopes; 2. Only on the eastern slope, and 3. Only on the western slope. Those of the last list were collected in the earlier part of the season, and a remarkable number are the same as those of my list for the eastern slope during the same months. Different localities and seasons yield different results, but complete collections would reveal no abrupt transitions; Iowa and Utah, for instance, have different floras, but any fifty or one hundred miles between, even at the summit of the Rockies, will show only the most gradual substitutions. One form disappears, a new one appears, but this occurs with a change of locality in any direction. On the plains of the Platte and its tributaries Cleome integrifolia only is found, while on Wind River and its tributaries Cleome lutea is the only form.

INTRODUCED PLANTS.

By introduced plants reference is made only to such as grow without cultivation. Most of them may properly be called Weeds." This is an ever-growing list and will soon include a large part of those familiar to the eastern farmer. The extension of our agricultural interests of course includes the importation of seed, and rarely is any kind of seed free from weed seeds. Some of our weeds, however, are native plants and thrive immensely

under cultivation.

Those of special interest receive notice in the proper place in the list, and possibly a future bulletin may deal with the weed problem in this state.

HARDINESS OF NATIVE PLANTS.

The power to withstand frost, so remarkably developed in mountain floras, has undoubtedly often been remarked upon before, but it is, nevertheless, unceasingly a cause of wonder. To see great beds of Phlox, Mertensia, Gilia, Actinella and scores of others in full bloom at times when the temperature at night is 5 to 20 F., below the freezing point is a phenomenon that can scarcely be explained. That reduced atmospheric pressure plays an important part in preventing injury, I think must be accepted, for the same plants at lower altitudes would perish. The following observation goes to prove this: Late in August in 1890, a plot of potatoes was noted in full blossom at Mountain Home, elevation about

9,000 feet. Observations on three successive days showed no trace of injury though on both of the intervening nights there were heavy white frosts and films of ice formed on water pails. Such a degree of cold would have absolutely killed potatoes at sea-level.

FLORAL CALENDAR.

In 1894 every effort was made to keep pace with the floral procession. At the altitude of the Laramie Plains, (7,000 feet), Spring opens comparatively late. April furnishes very few objects of interest to the botanist. The earliest flowers are Phlox caespitosa and Townsendia sericea, both of which expand their blossoms scarcely above the surface of the ground. These are soon followed by

some small Umbellifera, among which Cymopterus montanus may be noted. Toward the end of the month a few more begin to appear on the plains and in the foot-hills, all of which possess either large, fleshy, perennial roots, as Leucocrinum montanum, Musenium trachycarpum and Peucedanum nundicaule, or else they have large woody subterranean stems from which spring the small leaves and numerous flowers that spread out in dense mats or cushions upon the cold soil. Such are Astragalus spatulatus and Astragalus sericoleucus. Among the rocks in sheltered nooks are also two Mertensias, lanceolata and alpina. With the advent of May, or sometimes earlier, the little Drabas, glacialis and alpina tinge the naked rocks with yellow. In the moister canons our earliest Buttercup, Ranunculus glaberrimus, and the Wind-flower, Anemone patens Nuttalliana, are found.

Very slowly through May, for cold days and snowstorms are far from rare, the number grows so that the diligent observer may find several score. From this time on the forms crowd upon each other in rapid succession and one soon loses track of the order of their coming. June is the floral month of the plains, July of the lower mountains and August is the month of months in the high altitudes. September has something of worth everywhere and a few forms linger late into October.

BOTANICAL WORK IN THE STATE.

So far as I have been able to learn there are no other workers in systematic botany in the state, nor are there any other herbaria, public or private. On this account I have been unable to make comparison of our specimens with those from other localities in the state.