14 THE STORY OF PLANT LIFE 



hastening on of the reproductive process, and the 

 seeds to the distributive agencies preparatory to 

 germination, in which stage the seed reacts towards 

 the stimuH of water, Hght and oxygen. 



Thus, then, the sensibiHty of a plant is localised in 

 different organs, all elaborated with a view to ultimate 

 nutritive and growth functions. There is a division 

 of labour, but no co-operative force or system, such 

 as is seen in the nervous system of animals. There 

 may be analogy here, but no real parallel, except 

 physiologically speaking. 



12. Reproduction, Special Contrivances for 

 Race Perpetuation. 



Some of the organs of a plant are vegetative, as the 

 root, stem, and leaves. These have special functions 

 connected with nutrition and growth. But they are 

 also capable of propagation. Roots divide and give 

 rise to new plants. Stems may multiply, and as 

 rhizomes, etc., give rise to new plants. Leaves may 

 develop buds which may root and become separated, 

 and thus also give rise to new individuals. 



The other organs are the flowers which are repro- 

 ductive organs, which by a process of cell-division 

 and subsequent cell-fusion and multiplication, pro- 

 duce a new individual with the original germ-plasm, 

 but without the soma of the parent individual, the 

 germ-plasm itself giving rise to the new body-plasm. 



In vegetative propagation there is no such inter- 

 change of sexual elements; the plant cells extend 



