114 



layers are from 4 to 5 in number; the cells measuring 67;/ 

 by 120/z in height (highest measure). 



In specimens from Hjortlund, Mölhede, and the Botanic 

 Garden in Kjøbenhavn the layers are from 2 to 3 in number; 

 the cells measuring about 67 ц in height. 



In the specimens from St. Moritz the palisade-tissue was 

 found to be of a still greater thickness, but perhaps we are 

 here dealing with an Alpine or Subalpine species; and as it is 



contrary to what is usually 

 found that the thickness 

 of the palisade-tissues 

 should increase the farther 

 we advanced northwards, 

 I do not altach any great 

 importance to the facts 

 mentioned above, the mate- 

 rial being too scanty for 

 any reliable conclusions to 

 be based upon it. 



The upper layer of the 

 palisade-cells slants some- 

 what towards the apex. 



Large intercellularspa- 

 ces occur in the spongy 

 parenchyma, which is 

 formed by cells which 

 branch but slightly and are 

 transversely elongated. Tannin occurs in all the elements of 

 the leaf. 



Stereom is very slightly developed, in correlation with the 

 much-thickened epidermis. 



The stem. The primary outer cortex (cf. Segerstedt) con- 

 sists of a regular, much cuticularized epidermis without stomata, 

 beneath which is a tissue consisting of fairly homogeneous, 



Fig. 27. Arctostaphylos IJva-ursi. 



Transverse section of stem, x 180. 

 (Denmark: Mölhede.) (Phot.) 



