127 
is not especially thickened. In the most internal cortex a few 
bast-cells occur. 
There is only a slight trace, or none at all, of difference 
between the spring and autumn wood. As may be seen in 
Fig. 37 annual rings evidently occur, but it is not always easy 
to distinguish their boundaries. 
The roots have not been investigated (Hesserman, p. 27). 
Vaccinium Myrtillus L. (Figs. 38—39.) 
Fig. 38. Vaccinium Myrtillus. 
The leaf. Cf. note p.81. 6, Stoma of the stem. 5, Hair from the margin of the leaf. 
(1, Tromsö; 2, 4, Stockholm.) (H.E. P.) 
