446 



STUDIES IN SEEDS AND FRUITS 



and Bidens tripartita^ two species that grow in wet stations by 

 the sides of ditches, ponds, and rivers. After three generations 

 the height of the plants was reduced from 17 or 1 8 inches to 

 5 or 6 inches, the fleshy stems becoming dry, woody, and wiry, 

 the length of the achenes being reduced by half. The details 

 of this experiment are given in Note 13 of the Appendix. 



What man effects after years of tedious labour in the 

 dwarfing of trees, nature accomplishes in the course of ages 

 through the rigid pressure of the life-conditions. It is even 

 conceivable that in time, by a still more severe treatment of 

 repression, man could accomplish what nature seems to have 

 aimed at in the case of the West African JVelwitschia. In 

 other words, he would be able to confine the growth of the 

 plant to its cotyledonary stage. It is arguable, indeed, that he 

 could carry this treatment so far as to destroy the possibility of 

 a special terrestrial existence, or, to put it in ordinary language, 

 he would restrict the life of the plant to the seed-stage. The 

 seed would be by no means devitalised ; but the conditions on 

 which the maintenance of its vitality depended would be only 

 those which the earth possesses in common with the cosmos. 



For the experimenter the seed would merely be a plant- 

 organism that could not proceed with its development on 

 account of the repressive influence of the conditions. Sub- 

 stitute nature for the experimenter, and we should regard the 

 seed as representing the organism's response to the iron-bound 

 cosmic conditions, whilst the subsequent stages of growth would 

 depend on the relaxation of the pressure of these conditions on 

 the earth's surface. The seed would thus represent the cosmic 

 life of the plant-organism, whilst the fully developed plant 

 would be regarded as its special terrestrial form ; and we might 

 almost hold that the flowering and seeding stage represents the 

 plant's efibrt to return to its general cosmic habit, the vegeta- 

 tive mode of reproduction being viewed as based on purely 

 terrestrial necessities. Under conditions where the pressure 

 of the life-conditions is much less than prevails on our planet 

 it is conceivable that the whole plant would be " proliferous." 



