CH. II] THE PODOSTEMACEAE 23 



by anj^thing unfavourable in the spot upon which it is trying to 

 grow, by mere late arrival as compared with its competitors, and 

 so on, cannot survive in such a struggle, unless the handicap 

 imposed by one thing is compensated by a start in some other. 

 The actual winner or winners will be mainly picked out by chance, 

 and will in all probability be derived from parents that are 

 already living somewhere close by, and which may therefore be 

 looked upon as already adapted to the climate and other condi- 

 tions. In all probability this adaptation will be to a reasonably 

 large range of temperature and other climatic conditions, for 

 unless this were so, survival would be very improbable in most 

 places. There is also reason to suppose, that if it be done slowly 

 enough, a species may, as it moves slowly about the world, 

 become slowly acclimatised to other conditions, for the range of 

 some species is so enormous, and includes such varied condi- 

 tions, that without some possibility of this kind it is difficult to 

 understand. 



