yS The Firs 



than the other Firs. The bark is 2 to 4 cm. thick, shallowly fissured and broken 

 into irregular close, light red-brown to nearly white scales; the younger bark is 

 thinner, smoother, and gray or nearly white. The twigs are stout, rough, hair}-, 

 orange-brown, becoming smooth and Hght gray to nearly white. The winter buds 

 are subglobose, about 10 mm. long, covered by pointed brown scales, and are 

 resinous. The leaves are crowded, becoming erect by the twisted base, narrowly 

 linear, 2.5 to 5 cm. long, rather thick, bluish-green, shining, becoming darker with 

 age, blunt or notched at the apex, grooved on the upper side; a cross-section shows 

 two resin-ducts well within the pulpy part of the leaf; the leaves on the lower and 

 sterile shoots are thin, closely appressed, and sometimes stiff-pointed; those on 

 upper fertile branches are somewhat thicker, usually sharply thick-pointed, and 

 scarcelv half the length of the lower. The staminate flowers are cyHndric, 15 to 

 20 mm. long, 5 to 7 mm. thick, of a bluish color, the pistillate flowers being 2 to 

 2.5 cm. long, I cm. thick, and dark purple. The cones are oblong-cylindric, taper- 

 ing slightly toward each end from the middle, rounded or flattened at the apex, 

 6 to 10 cm. long, dark purple and slightly haiiy; the scales, which vary greatly in 

 outline, are usually fan-shaped, slightly longer than broad, 2 cm. long, about three 

 times the length of the bracts, which are oblong-ovate, irregularly toothed, rounded, 

 dark brown and abruptly long-tipped. The seed is about 8 mm. long; its wing, 

 which is nearly as long as the scale, is bluish at first, changing to brown. 



The wood is soft, w^eak, not durable, whitish to pale brown; its specific gravity 

 is about 0.34. It is \er\ little used as a commercial lumber. 



Its slow growth makes it rather undesirable for ornamental planting, although 

 its narrow form adds a pleasing variety to plantations of coniferous trees. 



The oleoresin is collected and used in the West like the Canada Balsam. 



4. SILVER FIR Abies concolor Lindley and Gordon 



This Fir, also called White balsam, Colorado white balsam, Colorado white 

 fir, and Balsam fir, occurs from the mountains of Oregon to southern California 

 and Lower California and eastward to \\ yoming, New Mexico and northern 

 Mexico, at elevations of from 1200 to 3300 meters, sometimes forming almost 

 exclusive forests and reaching a maximum height of 75 meters, with a trunk diame- 

 ter of 2 meters, though in its eastward range it seldom exceeds half this size. 



The bark of ver}^ old trees is often 15 cm. thick and deeply furrowed into broad 

 rounded ridges and broken into angular scaly plates of a reddish brown to light 

 gray color; that on younger trees is quite smooth except for many " balsam blisters," 

 which yield, when punctured, an abundance of oleoresin. The twigs are smooth, 

 shining, and dark orange, becoming gray or brown with age. The winter buds 

 are nearly globular, 7 to 12 mm. long, covered with blunt yellowish scales, and ver\' 

 resinous. The leaves are flat, linear, 3 to 6 cm. long, pale bluish green, often with 

 a bloom when young, dull green with age, slightly channeled above, rounded or 

 slightly notched at the apex on the lower branches, shorter, thicker, erect and 



