34 
PHARMACEUTICAL BOTANY 
3. Inner cortex of several layers of more or less isodiametric cells 
(cells of nearly the same length, breadth and thickness) with thin 
cellulose walls and containing stored starch surrounded by a proto- 
Fig. 12 .—Dryopteris filix-mas —Plant and section through pinnule and sorus. 
(Sayre.) 
plasmic investment. These cells conduct sap by osmosis and 
store food. Between the cells are to be noted intercullular-air- 
spaces, many of which contain internal glandular hairs. 
