122 
walls of the guard-cells and of the neighbouring cells is euti- 
cularized. The palisade-cells occur in several layers and are 
about 50 » in length. In regard to the palisade-tissue the 
Subarctic and the Arctic specimens do not appear to be in 
any way inferior to the Danish specimens (of the typical species). 
Fig. 33. Vaccinium Vitis-idea. 
Transverse section of stem. >< 180. (Greenland.) (Phot.) 
In shade-forms (which, as is well-known, always accompany light- 
forms), Subarctic specimens of which, however, I have not had 
for investigation, the elements of the leaf are naturally reduced 
in size (especially the palisade-tissue). The spongy parenchyma 
is not much branched and has very large intercellular spaces of 
