FLOWEES, SKUITS AND SEEDS. 77 



from the seed as soon as it is mature, and before drop- 

 ping from the cone. In the Pines especially, we find a 

 wide variation in this respect, for in some species, like 

 those of the Northern Pitch Pine {Pinus rigida), figure 

 40, the wing of the seed is three or four times the 

 length of the seed, and it adheres until the seed has been 

 widely scattered, but in those with larger seed, such as 

 the Nut Pines (P. edulis) and others, the wings 

 become detached before, or at the time^ the 

 seeds fall from the cone. 



While wind and water, birds and mammals 

 of various kinds, assist in the distribution of 

 seeds, there is no discrimination in these 

 natural processes, and the seeds of worthless 

 and pestiferous plants are just as likely to 

 spread over the earth's surface and grow as the most 

 valuable and useful. 



Vitality of Seeds. — Perfect and mature seeds, as 

 I have said elsewhere, are living organisms, within which 

 there can be no absolute cessation in the action of the 

 living principles or vital forces, for when this occurs the 

 seed dies, and a purely chemical change follows, however 

 slow and protracted it may prove to be. Sometimes the 

 vital actions may appear to be almost suspended, either 

 under normal or abnormal conditions, but they are never 

 absolutely quiescent, and while some kinds of seeds may 

 retain their vitality for many years under favorable con- 

 ditions, there is a limit to individual life even among 

 seeds. No known species will remain alive for "ages," 

 as has been so often asserted by persons whose imagina- 

 tion seems to have been far more fertile than their 

 knowledge was profound. It has been frequently claimed 

 that Wheat, and other kinds of grain, taken from the 

 Egyptian tombs and the wrappings of mummies, where 

 it was deposited many thousands of years ago, has been 

 made to germinate and grow when planted, but there are 



