1897] NORMAL AND DISEASED ORGANS OF ABIES BALSAMEA 329 
the first year’s terminal and lateral shoots are about equally 
developed. In the second year’s growth, however, the vascular 
bundle, especially the wood of the terminal shoots, shows a 
decidedly increased growth over that of the lateral. Thus cross 
sections of the main and lateral axes taken from the same trees 
ive the tollowing radial widths of their principal parts: 
TABLE IV. 
bark Middle bark Inner bark 
Axes Epidermis and Primary Secondary Wood Pith 
periderm cortex cortex 
z 166 1348y 83u 240" 1520n 
a 132 49 96 192 610 
% S 220 1245 90 288 I4It 
< 
Q 
> 
z 3 160 830 85 224 720 
= s 249 736 84 im wie 
sal 256 64 119 324 
FE 260 970 240 1040 1440 
5 Eg 224 980 250 1318 1250 
sa ad 230 846 ais 1246 1373 
= 
eg 
> ~ 
$ 2 256 800 140 640. 5 
ay 4 225 384 128 280} 420 
~ 210 348 123 394 390 
From the second year on this increased growth of the wood 
and Secondary cortex of the main axes over that of the lateral 
ches continues. 
__ Outer bark.—The terminal shoots have no epidermal hairs. 
The epidermis, however, of the one year old lateral shoots has 
humerous short, one to five-celled hairs,2? the cells of which 
become thick walled. The cells are usually unequally 
: thickened and pitted (fig. zr). The epidermal hairs of the 
__ lateral branches thus differ from the marginal hairs of the bud 
_ Scales, which remain thin walled. Since the epidermal hairs 
= Compare Tubeuf, idid., p. 35. 
