1897] NORMAL AND DISEASED ORGANS OF ABIES BALSAMEA 319 
In the following table the most important differences in the 
structural units of the normal and diseased leaves are given: 
TABLE II. 
TABLE SHOWING THE COMPARATIVE ANATOMY OF THE NORMAL AND 
DISEASED LEAVES OF A. BALSAMEA. 
Leaf structures 
Normal leaves 
Diseased leaves 
Cuticle. 
Well develop ed. 
e 
th 
cting epi- 
Cuticle present, but less. 
developed. 
Epidermis. 
Cells thicker walled on 
outer than inner sides. Often 
laminated and provided with 
pore canals, 
Epidermal cells more irreg- 
one spa in normal; less thick- 
en d seldom ‘laminated, 
js aaa with pore canals. 
Stomata. 
on lower baer on 
More 
upper leaf surfac 
toward apex as the 
ber of hypodermal eat 
decreases. 
Like the normal, but fewer 
n both surfaces. Bands of 
wun have fewer rows. 
Well developed at basal 
— of leaf. Number of cells | 
creases from 
ase tow: 
cs as the number of sto- 
mata increases. 
Hypodermal cells wegen but. 
usually larger, thicker walled 
and a opens jan 
normal 
Cells pnt aggregated. 
e to three layers of 
has merece 
chyma. 
| present. 
ircular or nearly so. C 
ing. The latter are thick 
alled. 
One layer of — or 
e.g Ssgeclive ed cells, 
-formin, <lsigagh Sor 
bounding the er and 
pericycle. 
No distinction between pali- 
sade cells and spongy paren- 
Chlorophyll rarely 
Ir rregular ; varying in form 
ae ao account of the 
th 
e layer of 
pron a a cells. 
Endod: seldom  dis- 
singushe.- Cells irre — 
in moe d size. = distinc 
resi 
| and anti 
