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PHARMACEUTICAL BOTANY 



4. Endodermis, or innermost layer of cells of the cortex, whose 

 radial walls are lenticularly thickened. 



5. Pericambium, of a layer of actively growing meristematic 

 cells, which has the power of producing lateral rootlets. 



6. Radial nbro-vascular bundle of five xylem arms alternating 

 with as many phloem patches. Note the narrow spiral tracheae in 

 the xylem patches. 



PIG. 61. Photomicrograph of a transverse section of a California Privet root 

 of primary growth showing epidermis (e) ; hypodermis (k) ; cortex (c) ; endodermis 

 (en); pericambium (p); a xylem arm of the radial bundle (/) and pith (m). 



The section you have just studied illustrated in general the appear- 

 ance of any Dicotyl root of primary growth. 



B. Mount permanently another T. S. cut through the same root a 

 short distance above the first. 



Note that this is somewhat larger in diameter. Observe the root 

 hairs starting from the epidermis; a broad cortex; a large clear and 

 open looking endodermis; then pericambium; next, a central patch 

 of xylem showing a faint pentarch relation. Pushed out are five 



