THE SUCCESSION OF FOREST TREES. 35 



down an oak one commonly sprang up, and vice versa. 

 To which I have answered, and now answer, that I 

 can tell, that it is no mystery to me. As I am not 

 aware that this has been clearly shown by any one, I 

 shall lay the more stress on this point. Let me lead 

 you back into your wood-lots again. 



When, hereabouts, a single forest tree or a forest 

 springs up naturally where none of its kind grew be 

 fore, I do not hesitate to say, though in some quarters 

 still it may sound paradoxical, that it came from a 

 seed. Of the various ways by which trees are known 

 to be propagated, by transplanting, cuttings, and 

 the like, this is the only supposable one under 

 these circumstances. No such tree has ever been 

 known to spring from anything else. If any one as 

 serts that it sprang from something else, or from noth 

 ing, the burden of proof lies with him. 



It remains, then, only to show how the seed is 

 transported from where it grows to where it is 

 planted. This is done chiefly by the agency of the 

 wind, water, and animals. The lighter seeds, as 

 those of pines and maples, are transported chiefly by 

 wind and water ; the heavier, as acorns and nuts, by 

 animals. 



In all the pines, a very thin membrane, in appear 

 ance much like an insect s wing, grows over and 

 around the seed, and independent of it, while the 

 latter is being developed within its base. Indeed, 

 this is often perfectly developed, though the seed is 

 abortive ; nature being, you would say, more sure to 

 provide the means of transporting the seed than to 

 provide the seed to be transported. In other words, a 

 beautiful thin sack is woven around the seed, with a 

 handle to it such as the wind can take hold of, and it 



