326 BOTANICAL GAZETTE [NovEMBER 
which are smaller than the normal. In the third table the 
number of exposed and of inner scales of normal and diseased 
buds are given. 
From the above table one sees that the number of the inner 
scales does not vary much in the normal and the affected buds. 
The number of exposed scales, however, have been increased 
from 16 to 20 in the normal, to 24 to 30 in the diseased buds. 
More of the diseased scales are, therefore, provided with a cuti- 
cularized and sclerotic epidermis than the normal. The total 
number of scales has also been increased from 24 to 2g in the 
normal to 30 to 38 in the diseased. 
One reason for this increase in the number of scales in the 
diseased buds is their relative smaller size. The buds thus 
require more scales to cover the growing point, which is also 
larger in diseased than in healthy buds. 
The diseased scales, like the normal, have no stomata. The 
marginal hairs are present and as in the normal scales remain 
thin walled. Those of the outer scales are always filled with 
resin soon after the resin exudation begins. 
The outer exposed epidermis is composed of shorter and 
more irregular cells than that of the normal. Cross sections of 
the scales show that the outer wall of the epidermal cells 1s 
thickened and cuticularized. The thickening never extends to 
the side or inner walls. The walls are not more than half as 
thick as in the normal epidermal cells. The inner, upper ©P 
dermis is rarely thickened excepting at the base of the inner 
scales. 
The mesophyll, which is less developed than in the n 
scales, consists of larger but fewer cells. The resin canals are 
fewer, more irregular in size and form; more than two are never 
present. They contain fewer epithelial cells, which vary greatly 
in size. Many of the diseased bud scales have no resin canals. 
The endodermis, pericycle, and central vascular bundle, 
which in the ‘normal scales have been reduced to 4 few cells, 
ormal 
_ smaller than the surrounding mesophyll cells, are not ieee 
the diseased scales. 
Rete en eee ee 
