PHARMACEUTICAL BOTANY 



xylem mass surrounded by an outer phloem mass. Each bundle is 

 enveloped by a pericambium and an endodermis or bundle sheath. 



Histology of Lamina. In transverse and surface sections the 

 lamina or blade shows the following structural details: 



i. Upper epidermis, of wavy- walled, slightly chlorophylloid, flat 

 upper epidermal cells, devoid of stomata, but with rather thick 

 cuticle. 



FIG. 15. Transverse section of stipe of Dryopteris Filix-mas showing epi- 

 dermis (e) ; hypodermis (h) ; inner cortex (ic) ; concentric fibrovascular bundles, 

 one of which is shown at (&); endodermis (en); pericambium (p); xylem (#),< 

 and phloem (p). (Photomicrograph.) X 50.4. 



2. Mesophyll, of irregular shaped chlorphylloid cells, containing 

 abundant chloroplasts. Intercellular-air-spaces are found between 

 various cells which are larger in the lower than in the upper region. 

 Internal glandular-hairs are frequently to be discerned in many of 

 these spaces. 



3. Concentric vascular bundles or laminar veins, that distribute 

 sap to, and carry sap from the mesophyll. These are seen to be 



