(51) 



however, give the Pinon Pine its local popularity in the South- 

 west, for they are a delicacy to the people and when roasted are 

 much prized. The gathering of these so-called nuts constitutes 

 quite a little industry in the region and furnishes occupation for 

 many. 



General Discussion 



Now that we have completed our study of some of them indi- 

 vidually, let us consider the pines as a whole. 



All pines are evergreen. That is, though their needle-like 

 leaves are shed and new ones appear each year, only a portion of 

 their foliage is lost at any one time. Consequently, the trees as a 

 whole are always green. There is no regular periodic shedding 

 and renewal of the foliage all at one time, as in the deciduous 

 broad-leaved trees. 



The pines constitute the largest and most widely distributed 

 group of conifers. They are found throughout the Northern 

 Hemisphere only, from the Arctic Circle to Mexico and the West 

 Indies, North Africa, and the Malayan Archipelago; in tropical 

 and subtropical regions they are usually confined to the moun- 

 tains.* Including all the varieties that occur as a result of this 

 wide distribution and those that have arisen through garden prac- 

 tice, more than six hundred kinds of pines have been described. 



According to one authority, who recognizes sixty-six distinct 

 species scattered over the Northern Hemisphere, the distribution 

 is as follows : 



Eastern Hemisphere — 23 Western Hemisphere — 43 



1 exclusively African (Ca- 28 in western North America, 

 nary Islands) of which 12 are confined 



2 exclusively European to Mexico and Central 

 2 common to Europe and America 



northern Asia 15 in eastern North America, 

 4 about the Mediterranean of which 2 are exclusively 



Basin West Indian 



14 exclusively Asiatic 



* Most plants, if they enjoy a wide geographical distribution from north to south and 

 are normally inhabitants of temperate and northern climes, ascend to higher elevations 

 in the southern limits of their range This tends to lessen the contrast in temperature 

 and other environmental factors 



