The Leaves. 83 



121. The Cultivator Should Provide for Normal 

 Leaf Development. Since the protoplasm of the plant 

 is nourished by prepared food (58), and since food 

 preparation in most plants takes place almost wholly 

 in the leaves (120), it is of first importance that the 

 plant be so cared for as to promote normal leaf devel- 

 opment. Without this, good crops are impossible. The 

 plants must be grown far enough apart so as not to 

 unduly shade each other; insects and fungi must not 

 be permitted to prey upon them when it is possible to 

 prevent it; and the leaves must not be needlessly re- 

 moved or injured. The more severe the climate, the 

 more important is perfect foliage, because more reserve 

 food is required to endure a long, severe winter than 

 a short, mild one. 



122. How Far Apart Should Plants be Grown? 

 When the 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 in- 

 terfere 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 ex- 

 periment. 



123. Stem and Root Development Depend on the 

 Number of Leaves. Since the vascular bundles, through 



