68 



PR1XCIPI.KS AND PRACTICE OF PRUNING 



changes between the initial period of terminal bud forma- 

 tion (lateral for peach and plum) and the time of flower- 

 ing; (3) the exact date of differentiation of pollen mother- 

 cells and of the similar stage in ovogenesis ; (4) the period 



of origin of pollen 

 grains and of ovules. 



During the growing 

 season buds were se- 

 lected every week or 10 

 days and during the 

 dormant season at 

 longer intervals. They 

 were killed, fixed, em- 

 bedded, sectioned, 

 stained and mounted 

 according to approved 

 laboratory methods and 

 the various stages of 

 growth and develop- 

 m e n t recorded by 

 photomicrographs, of 

 which the original re- 

 port shows 106. It is 

 not necessary here to 

 detail these methods, so 

 we will pass to the 



67. General observa- 

 tions. The great 

 amount of work in- 

 volved in preparing mi- 

 crosopic sections made 

 it impossible to study a 

 large number of varie- 

 ties. At first four va- 

 rieties of apples, three 

 of plum and one each 

 of peach, pear and 



FIG. 50 GOOSEBERRY BRANCHES, 



YOUNG AND OLD 



A, one-year growth from root. Two or 

 three of the strongest of such shoots should 

 be allowed to grow each year to replace old 

 wood cut out after fruiting. Notice position 

 of buds and length of spines three in a 

 cluster. The buds should form spurs for 

 fruiting next season. B, five-year-old branch 

 of a much less spiny variety. Canes should 

 not be allowed to grow as old as this, but be 

 pruned out when three or at most four years 

 old. Bushes kept young by such pruning are 

 usually healthier than ones in which the wood 

 is older. Best and most fruit develops on 

 two and three-year wood. 



