A. II. Lees 17 



that the characteristic hiteral outgrowths arose from fruit buds instead 

 of from basal wood buds (PI. V, Fig. 9). From comparative examination 

 of material from Chelmsford and Long Ashton there appears to be a 

 greater tendency to form wood buds at the latter place than at the former. 

 This is probably connected with the different climates at the two places. 

 The result is that outgrowths are more in number and weaker in growth 

 since many weak buds are pushed instead of a few strong. In both cases 

 however the effect of a bushy type of growth is produced instead of a 

 thin type, though the manner of production is slightly different. 



When such reverted shoots were examined it was found that many of 

 the buds were abnormally small (Fig. 10). Instead of being the normal 

 oval shape they were angular like an inverted V and were only 2 mm. in 

 length instead of being about 6 mm. When such buds were dissected it 

 was found that the growing point had been killed and only some brown 

 dried up material left to mark its position. 



From previous experience of growing points being killed by mite 

 during the summer at Long Ashton it was impossible not to assume that 

 the same cause had produced this effect, namely mite attack. This 

 hypothesis was supported by the fact that big buds were often also 

 present though these were confined to the lower portion of the shoot 

 while the "killed" buds practically always occurred higher up. It is 

 reasonable to look upon these " killed " buds as having been more strongly 

 attacked or as being less resistant to mite than typical big buds and 

 it is possible to trace a complete series of buds showing various stages of 

 resistance to mite attack. 



At the bottom of the series where presumably the mite attack is 

 greatest and resistance is smallest come the "blind" buds (Fig. 10). In 

 this case no trace of a bud can be seen though the scar of the leaf in the 

 axil of which it should have been borne is clear. The bud above and 

 below it are usually quite normal. 



Next in the series come the inverted V-shaped buds. They are small 

 and consist of only about half the normal number of scales surrounding 

 the dead growing point. In this case presumably the attack was either 

 later or less strong or the growing point was more vigorous. Such buds 

 are not usually found low down on a shoot for reasons subsequently 

 explained. The next stage is normal in shape but smaller than a healthy 

 bud and shows a killed growing point. Such buds are not very common 

 and indicate that the killing process took place later than the last stage 

 but before any tendency to fruit bud formation had taken place. 



The next stage consists of buds resembling "big buds" in shape but 



Ann. Biol, v 2 



