The Evergreen Trees oe Colorado. 27 
The surface of young twigs, under a hand 'lens, appears fuzzy or short 
hairy. This can be distinguished even by the naked eye if the twig is held 
up so that its outline is seen against the sky. The bark of large trunks is 
seldom grooved or furrowed as in the blue spruce, but is broken into rounded, 
plate-like scales of a reddish brown color. 
The cones of the Engelmann spruce are seidom over one and a half 
inches long and the scales are often more rounded than those of the blue 
spruce. 
The Engelmann spruce reaches the highesl: levels Tof tree growth and at 
timber line forms distorted spreading mats of scrubby growth. It is the most 
abundant of spruces in Colorado and forms extensive forests on the upper 
slopes and along the mountain streams. In its range it extends in general 
southward from the mountains of Britisih Columbia through the interior 
mountain ranges of the continent to northern New Mexico and Arizona. It 
reaches its greatest beauty and size north of the United States boundary. 
The bark is sometimes used for tanning leather. The wood is light and 
soft and is extensively manufactured into lumber, railway ties and to some 
extent is used for poles. It is probably our most valuable timber tree. The 
Engelmann spruce is not often planted for ornament, but is well adapted to 
such use in this state. 
GENUS Pseudotsuga — douguass spruce. 
The members of this genus are tall, stately evergreens with 
much the same form as the spruces. They are nearly intermediate 
in some characters between the true spruces and the firs. The 
needles are single on the branchlets and are contracted at the base 
into a short stalk. They are soft, flattened, blunt at the tips and 
possess a prominent midrib in,the form of a narrow ridge on the 
lower side. When the needles fall they leave small rounded scars 
on slightly raised portions of the branch. In these respects the 
Douglass spruces resemble the true firs. The cones, however, are 
in most respects like those of the spruces in that they are pendulous 
or hanging and that they remain entire when mature. The cones 
are readily recognized, from those of the spruces, as well as other 
members of the pine family, by their feathered appearance, due to 
the presence of slender-toothed bracts that project from between 
the scales. This character is so prominent that these trees can be 
recognized as far as the details of the cones are visible. 
Only two species in this genus are known in North America, 
one of which occurs in Colorado. 
DOUGLASS SPRUCE, DOUGLASS EIR, RED EIR. 
(Pseudotsuga mucronata (Raf.) Sudw.) 
(Plates VI. b. e., IX. c., 5.) 
The Douglass spruce is known by a number of common names through¬ 
out i'ts range. It occurs among the hills and mountains of the greater por¬ 
tion of the Northwest, extending from British Columbia and Alberta on the 
north to northern Mexico and Texas on the south. I't is a tree of conical 
form when young. It reaches its greatest size in the moist climate near the 
coast of Washington and Oregon and in the western foothills of the Cascade 
mountains, where it reaches a height of 200 feet or more with a trunk some¬ 
times 10 to 12 feet in diameter. In the drier inland regions it is usually less 
