66 THE PLANT WORLD. 



plate which is really very excellent in depicting the foliage characters, 

 though a figure of the cone was not included because "those which 

 were brought by Menzies" had "been unfortunately mislaid." 



Of all the Pacific Slope trees the Douglas Spruce enjoys the widest 

 distribution and appears to be the best able to adapt itself to great dif- 

 ferences in soil and climatic conditions. From the coast to the eastern 

 slopes of the Rockies on the fifty-first parallel to the latitude of San 

 Luis Potosi, Mexico, where it is found "in ravines and on northern 

 slopes of the highest mountains," this tree is found under all kinds of 

 environmental conditions. In the Coast Range of Oregon, Washing- 

 ton and British Columbia, on the western slopes of the Cascade Range 

 and between the altitudes of 1,500-2,500 feet is the locality where it 

 finds its most congenial surroundings and is the scene of its greatest 

 development. The average size here attained is a diameter of five feet 

 with a height of 250 feet. Occasionally trees twelve feet in diameter 

 are found, and these may be without doubt regarded as the parents of 

 the present smaller growth. 



Of the environmental factors afi'ecting the growth of this tree, 

 moisture appears to be the most important. The largest growths are 

 found at the altitude mentioned above where the moisture, either as the 

 result of rain or melting snow or soil water, is abundant throughout the 

 year, or along the bottom lands near to streams. On the bench lands 

 which are subject to the droughts of summer, with seasonal extremes 

 of wet and dryness, the tree does not make so good a showing. 



When growing in the open, young trees of Douglas Spruce assume 

 a conical form with a broad, rounded base, very similar in shape 

 to the Norway Spruce as it grows on our lawns. The upper branches 

 stand at an angle of about 45° with the horizontal, while those below 

 gradually come more and more into a position at right angles to the 

 trunk, with their outer ends turning upward, and supporting a mass of 

 slender, pendulous branchlets. Older trees in similar situations have a 

 long oval form, the contraction of the outlines below being due to the 

 drooping of the lowermost branches. When growing in the forest the 

 first limbs on trees of the average size are found at a height of T5-100 

 feet. The trunks are then straight and columnar holding their diameter 

 from base to crown in a remarkable way. 



Although the Douglas Spruce has a distinctly spruce like halfit, it 

 varies from that genus in the form and structure of its leaves. These are 

 directed in difi'erent planes, slender, flattened and slightly tapering from 



