THE INITIATION OF THE REPRODUCTIVE PROCESSES 187 



season is a matter obviously difficult of determination. Indirect 

 evidence, however, points to this possibility and suggests that fruit buds 

 may be initiated at any time when conditions are favorable. It is 

 certain that a spur after forming a leaf bud may start into second growth 

 and then form a fruit bud, all during the same growing season. 



Magness^^^ has traced the development of axillary buds. He finds that: 

 "axillary buds originate very close to the tip or apex of rapidly growing shoots. 

 As the shoot elongates, the leaves are given off at the side of the growing point, 

 and the young bud appears first as simply an undifferentiated mass of rapidly 

 dividing cells in the axils of these leaves ... no primordia were found de- 

 veloping in the axils of leaves that were not fairly well formed. 



"The buds developed very rapidly and those subtended by half-grown leaves, 

 1 to 2 inches above the terminal, were well differentiated, with a growing point or 

 apex, and bud scales being rapidly formed. The cells of the growing tip were 

 not well differentiated and this, with the high staining reaction of this region, 

 indicated that much growth was still taking place." By July 9 some of the older 

 axial buds had nearly reached the condition in which they would pass the winter. 



Time of Differentiation.^ — Drinkard"^ reported that fruit bud differ- 

 entiation in the Oldenburg apple occurred about June 20 in Virginia. 

 Goff^^ found the first clear evidence in the Hoadley apple on June 30 in 

 Wisconsin. Bradford'^ in Oregon found similar stages during the first 

 10 days of July, though resting stages of leaf buds were apparent in May. 

 The earliest differentiation observed by Kirby^"^ in Iowa was about the 

 first of July. 



In the pear it was observed in Virginia in samples of Kieffer taken 

 about the middle of July, somewhat later than the initial period for the 

 apple. ^^ In Wisconsin evidence was found in the Wilder Early on July 

 21.^^ Albert first found differentiation in the pear early in August 

 In the Champion quince Goff found embryonic flowers in bud examined, 

 late in the autumn, but did not determine the exact period of their 

 inception. Alber't found differentiation in the Japanese quince in August. 

 In the Luster peach initial stages of flower formation were observed in 

 Virginia the first week in July;''^ Quaintance^^^ in Georgia found no 

 indication of differentiation in Demming's September peach on June 14, 

 but on July 23 he reported: "the embryo flower is well under way 

 and the calyx lobes are quite pronounced." Apparently, then, the initial 

 stages must have occurred late in June. Goff,^'' working with a 

 Bokhara peach, considered that "flowers began to form about the middle 

 of September the past season." At Davis, California, the first evidence 

 of differentiation in the almond has been reported as about Aug. 18. ^^^ 



The plum as investigated by Drinkard shows some variation in the 

 time of initiation of fruit buds. Whitaker, one of the Wildgoose group, 

 gave no evidence until the first week in September; "observations on sev- 

 eral varieties of Japanese plums showed that the initial formation of fruit 



