26 The Colorado Experiment Station. 
B. Needles less rigid and sharply pointed, surface of the twigs among the 
needles finely pubescent or hairy; cones about 4 c. m. (1% in.)' long. 
2. Picea Engelmanni. 
BLUE SPRUCE, COLORADO BLUE SPRUCE, SILVER SPRUCE. 
(Picea Parryana (Andree) Sarg.) 
(Plates VI. d., VIII., IX. b.) 
This is one of the most admired and widely known evergreens and is 
certainly the handsomest of the spruces when well grown. It is somewhat 
limited in range, being found in Colorado and 'eastern Utah and northward 
inito Wyoming. It commonly grows in small groups or groves along the 
streams in the mountain valleys and parks. It usually reaches a height of 
seventy-five to one hundred feet, occasionally taller, with a 'trunk one to 
two feet in diameter. The leaves vary in color from bright green to 
silvery igreenish blue—the new growth being more distinctly bluish 'or sil¬ 
very than the nlder foliage. Y'oung trees are often very symmetrical and 
beautiful. When oid the tree may become som'ewhat ragged and open and 
the color of the foiiage may lose a degree of its blueness. 
The bark is broken into rather small, oblong scales and on old trunks 
becomes thick and furrowed or grooved lengthwise. This charactier helps to 
distinguish the blue from the Engelmann spruce, the latter having the bark 
broken into rounded plate-like scales even on old trunks. 
The cones consist of numerous thin scales narrowed toward the tips. 
They are usually prominent objects, as they hang in clusters in the upper 
part of the tree. 
The wood is soft, light and weak and is sometimes used for lumber 
and fuel. 
The blue spruce is largely planted for oranment and when well grown 
forms most beautiful specimen trees. For this purpose the bluest specimens 
are selected by the nurserymen, as the price which they bring is high in 
propertion to the blueness. This tree is well adapted to the formation of 
hedges and when well tended may be made impassible even to the smaller 
animals. 
The blue spruce m'ay be grown from seeds, gathered preferably from 
the bluest specimens, or native seedlings may be dug from the mountains 
where they occur. If wanted for specimen trees only the bluest should be 
saved, although the greener plants are equally useful for hedges and wind¬ 
breaks. The finest specimens are usually obtain'able through reliable nur¬ 
serymen ■who grow them in large numbers, the best ones being propagated 
by grafting. 
The blue spruce is at its best only when grown in a moist soil and un¬ 
der conditions of cultivation. When clothed in the new growth of the sea¬ 
son such trees have the appearance of being frosted with pale blue, at which 
* season they are unexcelled in beauty among trees. 
THE ENGELMAN spruce. 
(Picea Engelmanni (Parry) Engelm.) 
(Plates VI. a. c., IX. a.) 
The Engelmann spruce is frequently confused with the blue spruce, 
■which it often greatly resembles. It is a much larger tree than the blue 
spruce, in its northern range often growing to a height of 150 feet with a 
trunk four to five feet in diameter. Old trees are apt to be less regular in 
form than the blue spruce and the color is seldom so blue as the latter. The 
needles are less rigid and sharp than those of the blue spruce, so that an 
experienced nurseryman can usually distinguish the two by grasping the 
foliage with the bare hand. The leaves, furthermore, possess a disagreeable 
odor when bruised. 
