82 Principles of Plant Culture. 



\23. How Far Apart Should Plants be Grown? When 

 tlie finest developed plants, or parts of plants, as fruits, 

 flowers, leaves, stems or roots is desired, the plants should 

 not be grown so near together as to interfere with each 

 other's leaf or root development. But when the largest 

 crop from a given area is of more importance than the 

 development of the individual plant, as with grain crops, 

 the loss from a limited amount of shade and crowding 

 will be more than made up by the increased number of 

 plants. In this case, the amount of crowding that will 

 give the maximum yield will depend much upon the 

 fertility and moisture of the soil, and must generally be 

 determined by experiment. 



124. Stem and Root Development Depend on the Number 

 of Leaves. Since the vascular bundles, through the 

 formation of which the stem and root increase in diame- 

 ter, originate in the leaves (68), the size and firmness of 

 the stem and the root depend somewhat upon the num- 

 ber of leaves the- plant bears. The more leaves it has, 

 the more solar energy it can transform into plant tissue. 

 The stem is larger beneath a vigorous leafy branch, and 

 if cut off some distance above a branch, the part thus 

 deprived of its foliage ceases to grow, unless it develops 

 new leaves. Trees growing in the dense forest, where 

 their lower branches continually perish through lack of 

 light, have tall, but very slender trunks, and their wood 

 is soft because it contains comparatively little fibrous 

 tissue, while other trees of the same species, in the full 

 light of the open field, through the large amount of solar 

 energy absorbed by an immense number of leaves, 

 develop massive trunks, of which the wood, being 



