56 



POMOLOGY 



the tree, for it must be remembered that the type of early 

 activity manifested by the growing tree is controlled quite 

 as much by the character of its reserves as by the materials 

 which it absorbs from the media surrounding it. It is the 

 joint interaction or balance of the two which determines 

 the character of growth. 



52. Relation of these materials to flowering of plants. — 

 (See Fig. 22.) A favorite theme of speculation by botanists, 



Class 4 



Fig. 22. — Diagram to illustrate the hypotheses involved in Classes I, 

 II, III, and IV. To right of dotted line: fruitfulness will increase 

 for a time as vegetation decreases from the maximum, but will then 

 decrease as vegetation approaches the minimum. Going in the 

 other direction, as vegetation increases from the minimum fruit- 

 fulness will increase for a time, but vegetation will persist beyond 

 fruitfulness in either direction. To the left of the dotted line 

 vegetation may either decrease from the maximum or increase 

 from the minimum without affecting fruitfulness provided the 

 plants are in the condition described in either Class I or II. 



horticulturists, and others interested in vital phenomena, 

 has been the causes that underlie the flowering and fruiting of 

 plants. Horticulturists have usually approached the problem 

 by means of the field-trial route. Practically the whole cate- 

 gory of cultural practices has been brought into play in 

 attempting to regulate fruitfulness. But of special promi- 



