224 RHIZOMES AND ROOTS. 



(107) Elecampane Root. 



The root of Inula Helenium, Linn. (N.O. Composite). 



The root presents the following structure : 



(1) Cork, consisting of several rows of brown flattened cells, 

 which in surface view are polygonal and axially elongated. 



(2) Cortex, the cells of which are polygonal and tangentially 

 elongated ; in this tissue oleoresin ducts occur. 



(3) Bast Ring, traversed by wide medullary rays and containing 

 large oleoresin ducts. 



(4) Wood, divided by medullary rays of varying width into 

 wedge-shaped bundles, each of which contains radially elongated 

 groups of vessels, embedded in parenchymatous tissue, and 

 numerous oleoresin ducts. Some of the bundles are supported 

 by fibres with thickened lignified walls. The parenchymatous 

 cells of cortex, bast ring, and wood, contain an abundance of 

 inulin in colourless angular masses which dissolve without 

 swelling when heated in water. 



The diagnostic characters of powdered elecampane are : 



(a) The abundance of inulin. 



(b) The absence of starch and of calcium oxalatc. 



(c) The abundant parenchymatous tissue. 



