66 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



Key to the species 



1. Resin ducts of the leaves near the lower epidermis; cones grayish green; bracts 

 of the cone scales with a short triangular tip; cones 7 to 12 cm. long. 



1. A. CONCOLOR. 



1. Resin ducts of the leaves central; cones dark brown purple; bracts of the cone 

 scales with a long, subulate tip; cones 5 to 10 cm. long (2). 

 2. Old bark moderately thick, light gray to grayish brown. 2. A. lasiocarpa. 

 2. Old bark very thick and spongy, yellowish white 3. A. arizonica. 



1. Abies concolor (Gordon and Glendinning) Hoopes, Book of Ever- 



greens 220, 427. 1868. 



Picea concolor Gordon and Glendinning, Pinetum 155. 1858. 



Rim of the Grand Canyon (Coconino County) to the Chiricahua 

 Mountains (Cochise County), Santa Catalina Mountains (Pima 

 County), and Hualpai Mountain (Mohave County), 5,500 to 9,000 

 feet. Wyoming to Oregon, south to northern Mexico. 



White fir. In Arizona, where this is much the commonest species 

 of fir, it attains a height of about 30 m. (100 feet) and the massive 

 trunk a diameter of 1 m. (40 inches). In young trees the crown is 

 symmetrically conic and sharp pointed, but becomes more or less 

 irregular and rounded at the summit. Where the trees are widely 

 spaced, the branches extend nearly to the ground, but in crowded 

 stands one-half or more of the trunk is often bare. The bark, smooth 

 and brownish gray at first, becomes very thick, hard, deeply furrowed, 

 and ash-colored. A limited quantity of the soft, coarse-grained, light- 

 colored wood is sawed in Arizona . 



The writers are indebted to Elbert L. Little, Jr., for bringing to 

 their notice what seems to have been the first effective publication of 

 the name Abies concolor. 



2. Abies lasiocarpa (Hook.) Nutt., North Amer. Sylva 3: 138. 1849. 



Pinus lasiocarpa Hook., Fl. Bor. Amer. 2: 163. 1842. 



Kaibab Plateau and Navajo Mountain (Coconino County), Es- 

 cudilla Mountain and White Mountains (Apache County), Pinaleno 

 Mountains (Graham County), also reported from the Santa Catalina 

 Mountains (Pima County), 8,000 feet and upward. Alberta to 

 Alaska, south to northern New Mexico, Arizona, and Oregon. 



Alpine fir. Tree up to 27.5 m. (90 feet) high and 0.6 m. (2 feet) in 

 trunk diameter, but much dwarfed at high elevations. The crown is 

 elongate, narrowly conic, pointed, with branches often extending 

 nearly to the base of the tree. The bark, smooth and ashy gray or 

 whitish at first, becomes shallowly furrowed and gray or grayish 

 brown . 



3. Abies arizonica Merriam, Biol. Soc. Wash. Proc. 10: 115. 1896. 



Abies lasiocarpa var. arizonica (Merriam) Lemmon, Sierra 

 Club Bui. 2: 167. 1898. 



San Francisco Peaks (Coconino County), the type locality, 8,500 

 feet and upward. Reported also from Colorado and New Mexico. 



Corkbark fir. This doubtfully valid species seems to be distin- 

 guishable from A. lasiocarpa only by the usually thicker, spongier, 

 and lighter-colored bark. None of the other characters given by 

 Merriam and others as diagnostic appear to be constant, and there is 

 intergra dation even in the thickness and color of the bark. A form 



