ON VARIATION 



shed its seeds in this way, nor is there any 

 inducement in them or their covering to tempt an 

 animal to carry them away. 



They grow in clusters about the trunk and 

 branches, but remain attached to the tree. The 

 cones which hold them do not even open. Some- 

 times nine or ten crops of these seed cones may 

 be observed clinging to a parent tree. 



But whenever the woods are visited by a forest 

 fire, the cones are dried out by the heat, and the 

 seeds, released, fall to the ground and sprout. 



In the localities in which these trees grow, there 

 would be little chance for their seeds to germinate, 

 in fact, except after a forest fire had cleared the 

 ground. 



Against the competition of all of the hardy 

 underbrush to be found in those localities, the 

 mother tree, it would seem, fears that her seeds 

 will have but a poor chance. 



Yet when the fires have cleared the ground and 

 killed almost every other living thing, these seeds 

 spring up almost as quickly and almost as thickly 

 as grass on a lawn; and, competition removed, 

 they grow with surprising rapidity into the 

 making of a new forest. 



It has been observed that these trees grow 

 .usually along the sides of deep canyons where the 

 destructiveness of the fire is the greatest and only 



[99] 



