30 PROOFS OF HEREDITY [CHAP. 



Kauri pines of New Zealand, when taken from 

 exposed hillsides, yield timber much tougher 

 and more durable, and therefore more valuable 

 though less easily sawn than timber taken 

 from sheltered valleys. The ingenious timber 

 merchant endeavours on occasion to sell his 

 valley planks as the product of the hillside. 

 Climbing plants also ' use ' their tendrils." * 



So far from these being "uses of a limited 

 extent," they are really " adaptations by response 

 to changed advironments," such being of universal 

 extent, as far as wood or timber is concerned, 

 while climbing processes are extremely common 

 and of great variety; and in every case there 

 is the inductive evidence that the process of 

 climbing has resulted from a response to the 

 external conditions of life, and the climbing 

 adaptation has become hereditary, as explained 

 above in the case of the Japanese Ampelopsis 

 Veitchii. 



What he has here observed with regard to 

 the Kauri pine is applicable to all other trees ; 

 willows and poplars frequenting brook - sides, 

 etc., have quite worthless wood. On the other 

 hand in Cape Colony, being an excessively dry 

 country, all the trees are remarkable for the 

 durability and hardness of their wood. More- 

 over, this character is hereditary, for the 

 Araucaria imbricata of Chile is naturally a 

 strong xerophyte, and produces very hard wood 



1 Op. cit., p. 32, note. 



