FRUITING HABITS 



215 



determines whether a bud will remain a leaf bud or become a 

 fruit bud. With some fruits, buds may contain both leaves 

 and flowers. 



Apple. In general, differentiation in the apple starts about 

 the last part of June or the first part of July, but some buds 

 are differentiated later in the season. 



The exact time of differentiation varies somewhat with the 

 variety, locality, pruning and fertilizer treatment, season, and 

 other factors. Not all buds on the tree differentiate at the 

 same time. Normally spur buds are the first to differentiate, 



(Virginia Exp. Station) 



Fig. 75. Showing differentiation and development of flower buds of the 

 Oldenburg apple in Virginia, (a) June 30. (6) October 21. (c) January 6. 



followed about three weeks later by the lateral buds, and 

 finally by the terminal buds at the ends of the shoots. 



The sepals are generally the first noticeable parts to de- 

 velop, and these are commonly followed by the petals, stamens, 

 and pistils in the order named. Thus there is a gradual de- 

 velopment of the various parts throughout the summer, and 

 by the latter part of October the various parts of the flower 

 within the bud are quite distinct (Fig. 75). Only minor 

 changes occur during the winter, but the cells (pollen mother 

 cells), from which the pollen is eventually formed, gradually 



