MODIFICATION OF THE ORGANS OF PLANTS 83 



come about without a certain amount of conse- 

 quent degeneration. The chlorophyll has dis- 

 appeared, excepting a small quantity exhibited in 

 the upper and under 

 surfaces of the blades 

 of the leaves, in the 

 flower stalks, in the 

 central tentacles, and 

 in the petioles. 



3. Adaptation to 

 an aquatic life. The 

 adaptation of leaves, 

 particularly of sub- 

 merged leaves, to an 

 aquatic life entails 

 important changes, 

 and these changes 

 are invariably at- 

 tended by degenera- 

 tion. 



1. Owing to the 

 buoyancy of water, 

 submerged leaves are 



nr\f rloT^onrlonf rm FlG - 46 -~ Leaf of Drosera longifolia. 



not dependent on Near the topf an insect i8 in the %g of being 



nnv hirrVilv rlpvplrmprl captured and the suckers are bending over 

 any nigniy developed it Lower down is an insect reduced to a 



organic support, and cbitODOUS skeleton ' 

 the fibres and other thick-walled cells have con- 

 sequently degenerated to a great extent. 



2. There being no transpiration in. submerged 

 leaves and very little in floating leaves, the 



