12 BULLETIN 327, U. S. DEPARTMENT OF AGRICULTURE. 



IV, c). 1 A cross section of the leaf shows no resin ducts. A dis- 

 agreeable odor 2 is emitted by young leaves and young shoots when 

 crushed. The twigs are more or less minutely hairy and remain 

 so for about 3 years. 



The cones, which mature in a single season, are ripe by the middle 

 or latter part of August. Most of them are borne near the top of 

 the crpwn. By October the seed is usually all shed. Cones (PL IV) 

 vary greatly in length from about 1 to nearly 3 inches, the usual 

 length being about 1| inches. The cone scales also are very variable 

 in outline. They are commonly narrowed to squarish ends; some- 

 times, however, the ends of the scales are pointed, and occasionally 

 rounded. 3 When mature, and shortly after shedding their seeds, 

 the cones are somewhat shiny, and vary in color from light brown 

 to dark cinnamon-brown. They fall from the trees during autumn 

 or early winter. • The small winged seeds (PI. IV, a) are blackish- 

 brown. The seed-leaves are usually 6 (PI. IV, b). 



The wood of Engelmann spruce has thin layers of growth, is soft, 

 straight-grained, and of a very light yellowish to faintly reddish- 

 brown color. The sapwood is comparatively thick and as a rule only 

 a trifle lighter in color than the heartwood. The wood is lighter in 

 weight than that of any other native spruce, a cubic foot of seasoned 

 wood weighing about 21| pounds. Engelmann spruce is cut exten- 

 sively for lumber, which is used for general construction and to some 

 extent locally for interior finish. The timber is also much used for 

 temporary or light-traffic ties, telephone and telegraph poles, mine 

 props, fuel, house logs, and corral poles. 



OCCTJEEENCE AND HABITS. 



This species is essentially a tree of high altitudes (Map No. 3). 

 Demand for soil moisture limits its occurrence to high elevations or 

 to land moist from springs, seepage, or overflow. The lower range of 

 Engelmann spruce is confined to moist canyons or to protected north 

 slopes, while on other exposures it finds sufficient soil moisture only 

 at higher altitudes. Owing to lower temperatures and less intense 

 light in the North, favorable moisture conditions occur there at lower 

 elevations than in the South, hence, in general, the gradual lowering 



1 Occasionally trees have exceptionally flat leaves with distinctly slender, keen points, 

 in the latter character closely resembling lower-branch leaves of Picea parryana. The 

 presence, however, of minute hairs on the twigs serves to distinguish this form from the 

 blue spruce, which has smooth twigs. 



2 The odor is somewhat like that described for white spruce, but very much less 

 pronounced. 



3 Picea columbiana Lemmon (Gard. & For., X, 183, 1897) appears to be based upon the" 

 northern form of Picea engelmanni, in which the cone scales are aften more or less 

 rounded at their ends. This form of Engelmann spruce is the one occurring commonly in 

 Montana, Idaho, and British Columbia. Cone scales of Engelmann spruce growing in the 

 central and southern Rocky Mountain States generally have squarish ends. 



