244 The Great World's Farm 



ing at all in most places, although it is a perennial, and 

 although its seeds are so minute as to be easily wafted to 

 a great distance by the wind. So, .then, only one seed 

 out of the thousands borne by a single plant can come to 

 anything, and even that not every year, but only once in 

 several years; for as each plant lives some years, there 

 must be an increase in its numbers if but one new plant 

 grew up every year. 



That the seeds are scattered, and widely scattered, is 

 unquestionable, for seedlings have been found eight or ten 

 miles away from where any plants grew; but it is equally 

 certain that there is some effectual check to the plant's 

 increase, though what that check is remains unknown. 



It is plain, therefore, that the mere scattering of the 

 seed, however necessary as a first step, is far from being 

 enough to secure that the plant shall be able to establish 

 itself in a fresh locahty; and the farther the seed is 

 carried the greater the risk it often runs. Some plants 

 are much better able than others to adapt themselves to 

 altered circumstances, and these, of course, make the 

 better colonists; but even they may be quite unable to 

 effect a settlement, simply for lack of space. Others find 

 that soil, or climate, or situation do not suit them, and 

 soon die out for that reason. Others, again, though they 

 may find ample room, and all things else to their liking, 

 are quite unable to become permanent colonists because 

 they cannot fertilize themselves, and if there are not the 

 right insects to do it for them, they cannot produce any 

 seed. Such plants as have more than one "form," and 

 such as bear pollen and ovules on separate individuals, run, 

 of course, especial risks when they migrate, as one is 

 generally helpless without the other. 



