DEDUCTION. GENERAL INSTANCES. 165 



But other large families, normally composed of 

 non-climbers, contain one or a few climbing 

 species, as, for example, the hop in the nettle 

 family. 



The power to climb is so striking a charac- 

 ter, and is so plainly useful to the plant pos- 

 sessing it, that Darwin's theories would be 

 taxed with failure if they did not explain its 

 origin. But climbing plants are found through- 

 out the plant kingdom ; and they are not 

 descended from a common climbing ancestor, 

 for they possess nothing in common except 

 this one power to climb. ''Plants, "he said, 

 "become climbers in order, it may be pre- 

 sumed, to reach the light, and to expose a 

 large surface of leaves to its action and to 

 that of the free air. This is effected by the 

 climbers with wonderfully little expenditure of 

 organized matter in comparison with trees, 

 which have to support a load of heavy branches 

 by a massive trunk. Hence, no doubt, it arises 

 that there are in all quarters of the world so 

 many climbing plants belonging to so many 

 different orders." The very great advantage 

 offered to the climber has acted as a powerful 

 premium for the development of the capacity 



1 Journal of the Linnean Society, 1865; Botany, Vol. IX. 

 pp. 107, 108. 



