THE SILVA OF COLORADO 26 1 



Recently developed methods of seasoning and preservative treatment promise to make the 

 lodgepole pine valuable for railway ties and mine timbers. 



Montana to southern Colorado, west to California and Alaska. In the higher foot- 

 hills of Colorado. 



Genus 2. PICE A, The True Spruces 



Tall, conical, evergreen trees with tapering trunk and thin, scaly 

 bark. Leaves needle-shaped, four-angled or flattened (ours four- 

 angled) with sharp points. The leaves extend out from all sides of the 

 twig in bottle-brush fashion; they are not in bundles as in pine but occur 

 singly. Leaves jointed near the base, the lower part (sterigma) becom- 

 ing woody and persistent after the fall of the leaf. Bare twigs thus 

 appear roughened with short, truncate, elevations. Cones pendant, 

 chiefly on the upper branches. 



I a. Leaves rigid, needle pointed, blue-green or silvery, branchlets smooth or at least not 

 hairy. Cones about 7 cm. (2§ in.) long. Frequent in cultivation. Picea parryana 



lb. Leaves less rigid, abruptly pointed, having a somewhat skunk-like odor when bruised. 

 The branchlets are generally described as pubescent but are smooth in specimens 

 grown at high altitudes. Cones about 4 cm. (if in.) long. Picea engelmanni 



Picea parryana (Andree) Sarg. Colorado Blue Spruce. Leaves stout, 

 rigid, four-angled, mostly 25 to 30 mm. long but on cone-bearing branches shorter and 

 curved. Generally the leaves stand out from all sides of the branchlets but sometimes 

 the under surface of horizontal branches has few leaves. Color of leaves generally silvery 

 or bluish-green when young, becoming duller with age. Individual specimens differ 

 greatly in this regard. Cones about 7 cm. long. 



A tree of medium size. Bark broken into small oblong, platelike scales; on old 

 trunks thick and deeply grooved. Wood light, soft, weak; specific gravity 0.3740. 



Along the mountain streams of eastern Colorado, west to Utah and north to the Wind 

 River Mountains of Wyoming, occurring singly or in small groves. 



Much cultivated for ornament in this country and in Europe. There are numerous 

 horticultural varieties propagated by grafting. 



Picea engelmanni (Parry) Engelm. Engelmann Spruce. Leaves ridged above 

 and below so that they are rather four -sided; awl pointed; not so stiff as those of the blue 

 spruce. Leaves at first covered with a bluish or silvery bloom which disappears later; 

 slender, 25 to 30 mm. long on the ordinary branches but shorter on cone-bearing twigs. 

 Cones 3 to 5 cm. long. 



A large conical tree of the higher foothills and mountains; near timber limit a strag- 

 gling, prostrate shrub. Bark thin, broken into large, thin, loose scales. Wood light, soft, 

 close grained, not strong; specific gravity 0.3449. Frequently used for lumber and for 

 making charcoal. The bark has been employed for tanning leather. In some localities 

 the Englemann spruce has been largely cut for railway ties and to some extent for telegraph 

 and telephone poles. It should be valuable for wood pulp. 



