202 GRAND STRATEGY OF EVOLUTION 



It is not our purpose to discuss the various architec- 

 tural plans utilized by plant life. Their ways and 

 means of growth are comparatively uniform and bear 

 less directly on our problems than those of animals. 

 It will be sufficient to indicate, in one example, how 

 their achievements, as individuals, are definitely limited 

 by their initial constitution, the sources of their profits, 

 and the methods they must use to gain them. 



The more highly organized plants, for example, 

 have been compelled to adopt a distinctly dual, or 

 double ended system of growth, one set of organs in 

 the soil, a different set in the light and air. Thereby 

 special administrative difficulties are incurred in the. 

 conveyance and exchange of their respective products, 

 the receipt of their supplies and the storage of their 

 surplus. 



The roots must build their defensive lines against 

 the poverty, and the varied texture of the soil, and draw 

 from the soil its nourishment. The leaves must spread 

 their receptive fabrics to the sun and air, and construct, 

 or seek, their own defense against them. To these ends, 

 the plant makes large usage of its own dead and waste 

 materials, and preserves them within itself for support 

 and transportation. 



All these exigencies of the plant's inner life and 

 outer world place definite limitations on its powers of 

 growth, that cannot be exceeded without disaster. The 

 weight and area of leaf and branch cannot exceed 

 the sustaining power of stem and soil; nor can the 

 excursions of the roots and leaves in search of profit 

 exceed the limits of profitable exchange between 

 them. 



The Tightness of its living, the degree of its free- 



