120 
bog), nor on Novbr. 11, 1906 (Ruder Hegn (wood)). In the upper 
palisade-cells a red cell-sap occurs during winter, and then the 
contents of these cells always give a good reaction for tannin. 
But in the leaf tannin also occurs in the other cells of the 
Fig. 31. Vaccinium Oxycoccos. 
Transverse section of stem (Denmark). X 180. (Phot.) 
mesophyll. There is scarcely any other difference between the 
Danish and the northern specimens than the one indicated above. 
The stem. The primary cortex consists of a fairly com- 
pact tissue of parenchymatous cells with a rather slightly de- 
