252 RHIZOMES AND ROOTS. 



(121) Pellitory Root 



The root of Anacyclus Pyrethrum, D.C. (N.O. Composite) . 

 The root presents the following structure : 



(1) Cork, composed of several rows of brown tabular cells, 

 which, in surface view, are polygonal and do not exhibit any 

 definite arrangement. 



(2) Cortex , the cells of which are tangentially elongated near the 

 periphery of the root, but become isodiametric towards the wood. 

 In the outer portion of this tissue, which is often of small ex- 

 tent or even absent, there occur sclerenchymatous cells, the 

 walls of which are thickened in varying degrees, and also small 

 oleoresin ducts. 



(3) Bast Ring, which is divided into bast rays by very wide 

 medullary rays, in which there are distributed numerous large 

 oleo-resin ducts ; the bast rays are destitute of bast fibres. 



(4) Wood, which is traversed by rather wide medullary rays in 

 which there are numerous oleoresin ducts. The elongated 

 wedge-shaped vascular bundles contain pitted and reticulate 

 vessels, which are often grouped together. In the centre is the 

 primary wood surrounded by thick-walled fibres. The root con- 

 tains an abundance of inulin in the shape of irregularly angular 

 transparent masses in the parenchymatous cells of cortex, bast 

 ring, and wood. It does not contain any calcium oxalate. 



The diagnostic characters of powdered pellitory root are : 



(a) The abundance of inulin. 



(b) The absence of fibres and of calcium oxalate. 



(c) The presence of sclerenchymatous cells. 



