114 
layers are from 4 to 5 in number; the cells measuring 67 a 
by 120 in height (highest measure). 
In specimens from Hjortlund, Mölhede, and the Botanic 
Garden in Kjobenhavn the layers are from 2 to 3 in number; 
the cells measuring about 67 4 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 attach 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 intercellular spa- 
ces occur in the spongy 
Fig. 27. Arctostaphylos Uva-ursi. parenchyma, which is 
Transverse section of stem. x 180. 
(Denmark: Mélhede.) (Phot.) 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, 
