160 PLANT LIFE 
conceivable device which has not been actually 
put into practice by one or another of them. 
But whatever be the particular nature of 
the adaption in any given instance, its final 
significance, and its ultimate justification, is 
to be sought in the assistance it renders towards 
the proper discharge of the photosynthetic 
functions of the green surface. 
Plants which contain no chlorophyll—and 
there are vast numbers of them—have no 
use for the varied complications that circum- 
stances may render essential or ancillary to 
the green members of the vegetable kingdom. 
Indeed, it is not too much to say that all the 
beauty of form, all the elaborate structure, 
which is so copiously displayed by the vegeta- 
tive organs of trees and plants generally, 
spring from the possession of this substance 
chlorophyll, with its wonderful power of 
trapping and utilising the energy of the 
sunlight. 
But apart from all zsthetic considerations, 
and regarding the matter solely from the 
most material point of view, we may further 
assert that the elaboration of chlorophyll 
has been fraught with consequences to the 
whole organic world compared with which 
all the other structural products of evolu- 
tionary change sink into insignificance and 
obscurity. 
