32 BULLETIN 207, U. S. DEPAKTMENT OF AGRICULTURE. 



soils of canyon bottoms and in protected places on the lower moun- 

 tain benches. The tree's vertical range extends from about 4,500 to 

 nearly 8,400 feet elevation, but it is most abundant between 5,500 

 and 7,000 feet. Because of its great hardiness this species is one of 

 the most useful of southwestern junipers for maintaining a protective 

 woodland forest on exposed arid hills and lower mountain slopes. 



Alligator juniper endures moderate shade during the seedling stage 

 and for a few years afterwards, but requires full overhead light for 

 later development. Continued, dense side shade produces a long 

 clear trunk, and a short, thin-branched, open crown. 



This tree bears seed abundantly almost every year, and reproduces 

 itself plentifully whenever the berries find lodgment in washed or 

 broken soil. Reproduction is especially good in light shade where 

 old trees have been cut out. Severely pollarded trees and high-cut 

 stumps often sprout vigorously. Birds eat considerable quantities of 

 the berries and thus assist in disseminating this species, while in 

 seasons when food is scarce squirrels and other rodents eat a good 

 many of the seeds. 



LONGEVITY. 



Alligator juniper is a very long-lived tree. It grows slowly, how- 

 ever, even in the most favorable situations, and is extremely slow on 

 the least favorable sites. The exact age of very large trees has not 

 been determined. Trees from 12 to 20 inches in diameter are from 

 165 to 290 years old, while those from 3 to 5 feet in diameter must be 

 from about 500 to 800 years old. 



DROOPING JUNIPER. 



Juniperus flaccida S ch lechtendal . 



COMMON NAME AND EARLY HISTORY. 



Although very distinct in its general appearance from other 

 southwestern junipers, this species is doubtless unknown to many 

 lay people, and unfamiliar even to a good many foresters and botan- 

 ists, chiefly because in the United States it grows in an isolated and 

 little frequented section of the country. It is, in fact, essentially a 

 Mexican species, the principal part of its range being in Mexico. 

 The few stockmen and prospectors who have seen the tree know it 

 only as "cedar" or "juniper." The name " drooping juniper," derived 

 from the technical term flaccida, seems both appropriate and dis- 

 tinctive, in that it refers to the nodding or pendent habit of the 

 branchlets, which is a conspicuous and distinctive characteristic of 

 this tree (PL XXVI). "Loose-growing Mexican juniper" and 

 "loose-growing juniper" are book names applied about 50 years 

 ago, but neither of these appear to be appropriate, nor has either 

 been adopted in this country. 



