The Firs 73 



rounded obliquely connected ridges covered with thick closely adherent scales of 

 a dark red-brown color. The slender twigs are red-brown, slightly hairy, becoming 

 smooth, lighter-brown, and finally gray or brown. The winter buds are ovoid, 

 sharp-pointed, 5 to 7 mm. long, and covered by brown shining scales. The leaves 

 are 2 to 3 cm. long, about 2 mm. wide, slender, thick-tipped, appear 2 -ranked by 

 the twisting of the stalk, and incun^ed, dark blue-gray. The staminate flowers 

 are 2 to 2.5 cm. long, light yellow, and partly enclosed in a scaly involucre. The 

 pistillate flowers are ovoid-oblong, 2.5 cm. long, 1.5 cm. thick, greenish or green- 

 ish red. The ovoid cyhndric cones are abundantly produced near the top of the 

 tree, and remain on the branches for about a year after shedding their seed ; they 

 are short-stalked, 10 to 16 cm. long, about one half as thick; their orbicular con- 

 cave scales, 5 cm. broad, are thick, woody, broader than long, rounded at the top, 

 wedge-shaped toward the base, eroded on the margin, shghtly hairy and striate on 

 the exposed surface; the bracts, which are from i to 2 cm. longer than the scales, 

 jire widest above, and terminated by a central prolonged tip, and two shorter, 

 somewhat spreading, lateral lobes. The seed is triangular-obovate, 10 to 15 mm. 

 long, about 9 mm. wide, nearly black and shining above, dull and light brown 

 beneath, its wing broadest near the middle, shghtly longer than the body, and 

 obUquely rounded at the end. 



The wood is hard, strong, close-grained, brown and durable; its specific gravity 

 is about 0.45 ; it is sometimes sawed into lumber, but its principal use is for fuel. 



VI. THE FIRS 



GENUS ABIES [TOURNEFORT] MILLER 



HIS genus includes about 25 species of very symmetrical conic trees, 



some of immense stature, some, however, reduced to mere shrubs at 



great altitudes or in the high latitudes. They are confined to cold 



and temperate regions of the northern hemisphere, occurring in greatest 



variety in western North America. In addition to the ten species here described, 



one, Abies religiosa Lindl., occurs in the mountains from Mexico to Guatemala. 



Our species are all trees with bHster-hke excrescences on the bark, which, 



when punctured, exude a viscid oleoresin. 



The winter buds are enclosed in imbricated scales, some of which persist at 

 the base of the newly formed twigs for some considerable time, leaving, when 

 faUing, a circular scar surrounding the twig. The leaves are evergreen, sessije . 

 persistent for five to ten years, leaving a round scar when falUng. They are 

 spirally arranged, but by a twist of the base they appear as if 2-ranked. They 

 are flat, or in some species 4-sided, the margins often thickened and strongly 

 revolute; the apex is notched, rounded or pointed; the upper surface is usually 

 flattened or grooved, dark green and shining, and in some species has stomata; 

 the lower surface is usually marked by a row of stomata on each side of the midrib. 

 On old and fertile branches the leaves are usually shorter, thicker, and sharper 



