58 CONTACTS WITH DARWINISM IV [ch. vi 



It is clear that in adaptation to climbing a large part of the 

 adaptation, if not perhaps all, must be internal and physiological, 

 and we are inclined to think that it is to such adaptation that 

 the name should be practically confined, while such things as 

 climbing plants might be called suited to climbing. If a plant, as 

 will usually be the case, move only a very small distance from the 

 parent, it is probable that it will not need more than the minimum 

 of physiological adaptation to suit it to the new place, and so on 

 at every move. But such adaptation will not necessarily show 

 any morphological changes visible to the outside. If one look at 

 the distribution of such a widespread plant as Hydrocotyle 

 asiatica, which ranges from the plains of Ceylon, with a tem- 

 perature range of 70-90° F., to the south of New Zealand with 

 winter snow and frost and a weak sun, one finds it to be essentially 

 the same plant throughout. The Ceylon plants are suited to the 

 Ceylon conditions, the New Zealand to those of New Zealand. 

 But it is customary to speak of it as "adapted" to both. If it 

 suits them both, it must be just a case of luck, with local adapta- 

 tion going on as it has moved from one to another. One very 

 much doubts, after considerable experience with acclimatisation, 

 if seed from the plains of Ceylon would suit New Zealand without 

 a lot of previous physiological adaptation, or vice versa. 



Liberian coffee was gradually acclimatised to higher levels in 

 Java by carrying seed a little higher at each generation. In Ceylon, 

 when we tried to acclimatise the beautiful Cyperus Papyrus with 

 European seed, we failed, but seed from India was a success. 



The whole question of correlation of characters is an extremely 

 difficult one when looked at from the point of view of natural 

 selection. If large, it implies that most of the characters con- 

 cerned have no bearing upon natural selection, and do not 

 interfere with the results produced by the modification in the 

 first character, thus further implying that the change in that is 

 sufficient to carry the new species past the line of mutual sterility 

 that will usually divide it from the old. The characters of 

 climbing plants had some evident connection, for all were useful 

 in climbing, but that does not apply to the characters that one 

 finds correlated in an ordinary species, which have no apparent 

 connection of any kind, nor anything to which one can attach 

 any adaptational value. Their best explanation seems to be that 

 they have gone together in the apparently purposeless and un- 

 accountable way in which characters in mutations so often seem 



to go. 



