THE SILVA OF COLORADO 121 



seen from a distance. Cones pendulous, cone scales persistent; bracts with promi- 

 nent teeth giving the cone a fringed appearance. Three species of this genus are 

 known; one in Japan, the other two in western North America. One of these latter 

 occurs in Colorado. 



Pseudotsuga mucronata (Raf.) Sudw. Douglas Spruce, Red Fir 



Rydberg, Flora Colo. 8; Coulter, Manual 431 (as Pseudotsuga douglasii); 

 Sargent, Manual Trees of N.A. 53; Nelson, Key to Rocky Mountain Flora 6 (as 

 Pseudotsuga taxijolia) . 



Leaves rather soft, not rigid, flat, channeled above and ridged below, 20 to 35 mm. 

 long, dark yellow-green in color, narrowed to a short stalk; leaf scars not prominent. 

 Cones pendulous, 5 to 10 cm. long, the bracts projecting beyond the scales. Each 

 bract with two lateral teeth and the midrib projected as a rigid awn. 



A tree of handsome conical form, especially when young; reaching the greatest 

 size in the moist forests of Oregon and Washington. Bark on young trees smooth 

 and thin; on older trees very thick and deeply furrowed; sometimes used in tanning. 

 Wood hard; light red or yellow; specific gravity 0.5157; largely manufactured 

 into lumber in the Pacific Northwest where it is generally known as "Oregon pine" 

 or as "red fir." Used also for fuel, railway ties and piles. 



British Columbia and Alberta southward through hills and mountains to northern 

 Mexico and western Texas. 



Frequently planted as an ornamental and shade tree in Europe and the eastern 

 United States. Numerous varieties are distinguished in cultivation. It is propa- 

 gated easily from seed and has been recommended for reforesting of cut-over timber 

 lands in the central Northwest. 



Genus ABIES, The Firs, Balsams 



Tall, conical trees of colder regions and moimtain districts; with linear, flat, sessile 

 leaves, grooved above and having a notched apex. Although developed on all sides 

 of the branches the leaves generally bend so as to form flat masses of foliage. On 

 the upper cone-bearing branches the leaves are often curved and thick, with the 

 upper surface convex instead of grooved. Branches developed on the main trunk 

 in regular whorls; the branchlets show rather prominent circular scars where the 

 leaves have fallen. Flowers produced in early spring, the staminate flowers numer- 

 ous on the under sides of branches in the upper part of the tree; carpellate flowers 

 chiefly on the upper sides of topmost branches. Cones erect, purplish-black or 

 yellow, formed of closely imbricated scales; exuding a balsamic resin. The cone 

 scales and bracts separate from the axis while this is still on the tree. Hence com- 

 plete cones are never found under the trees but only scales and seeds. 



About 25 species are known of which 9 occur in North America. The best 

 known fir is Abies balsamea of the northeastern states and Canada. In this species 



