22 
covers the surface, and no trees are seen except cotton woods {Populus 
vionilifera) along the Missouri. The first ranges of the Rocky Moun- 
tains on this route along the Yellowstone River and in the Park are 
covered sparsely or densely with trees, the higher summits and ridges 
with Pinus flexUis, James, Abies grandis, and Tsuga Douglassii, Carr., 
while the foot-hills, and, in some cases the levels, are thickly set 
with Finns contorta. Dough, var. Murrayana, Watson. This latter is 
regarded by some as a distinct species {P. Murrayafia, Murr.), but is 
only, an upland form, which is larger and more spreading. Both vari- 
eties, however, grow in proximity in many parts of Oregon and 
Northern California. In the lowlands of the Park are dense thickets 
J 
tifoli 
The divide west of Helena is covered with scattered trees of 
X 
Douglass's spruce, which here reaches a height of one hundred feet. 
In the gorges which head in the mountains there' are a few trees, often 
of good size, of Pinus ponderosa, Doi'gl., but they are here out of 
place and belong properly to the arid country between the Rocky 
Mountains and the Cascade Range. 
In the valley of Clark's Fork and about Pend'Oreille Lake the 
forest growth is quite strong, the rocky cliffs and ridges are set with 
Douglass's and Menzie's spruces, while the lowlands sustain a crowded 
growth of slender trees belonging to three species which are charact- 
eristic of the Western flora, probably not crossing the divide. These 
are Pinus monticola, Dough, Larix occidentalis, Nutt., and Thuya 
gigantea, Nutt. Of these, the first has altogether the habit of our 
white pine in trunk, foliage and branches, but is at once distinguished 
by its longer and more slender cones. In the Cascade Mountains 
this species occurs sparingly over a large area, but I have never seen 
It elsewhere in such abundance as on Clark's Fork. The same is true 
of the Larix ; larger trees than any found here are scattered over the 
eastern slope of the mountains of Oregon, but they are comparatively 
rare. The Thuya extends from the sources to the mouth of the 
Columbia, constantly increasing in size; in the Rocky Mountains 
never attaining more than one-half the dimensions it reaches on the 
ower river. As we descend the valley of Clark's Fork the western 
hemlock {Tsuga Mertensiana, Carr.) begins to make its appearance; 
at first as shrubs or low trees simulating exactly the hemlock of the 
Ij^astern States, from which this has only a varietal difference. On 
the Lower Columbia it grows, like many other conifers, to be a 
majestic tree. 
Between the last ranges of the Rocky Mountains, near Pend' 
Oreille Lake and the Cascades, the prevailing and almost the only 
tree is Pinus ponder osa, Dougl. It scarcely forms forests here, but is 
scattered over the country in considerable abundance and attains a 
large size. 
Passing the gorge of the Columbia we come into the dense forests 
of the Pacific Coast proper, where the number and magnitude of the 
trees is greater than I have seen in any eastern or even tropical re- 
§'° j' r ^^^ ^""^^^ °^ several kinds here reach an altitude of three hun- 
dred feet, and often stand so near together that all undergrowth is 
