254 RHIZOMES AND BOOTS. 



(122) Rhatany Root. 



The root of Krameria triandra, R. et P. (N.O. Polygalese). 

 The root presents the following structure : 



(1) Cork, consisting of a number of cells with dark brown 

 walls ; in surface view they are polygonal. 



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

 elongated ; they have reddish-brown walls and contain 

 colouring matter and starch. The starch grains are either 

 simple or compound ; the former are sometimes rounded, some- 

 times conical or pear-shaped; the compound grains contain 

 from two to four constituents the shape varying with the 

 number and often stellate when there are three or four com- 

 ponent grains. The cortex is narrow and free from 

 sclerenchymatous elements. 



(3) Bast Ring, characterised by the presence of numerous 

 radially elongated bundles of sclerenchymatous fibres, with 

 moderately thick walls ; in transverse section these fibres appear 

 flattened. Some of the cells of the bast parenchyma contain 

 several small prismatic crystals of calcium oxalate ; the others 

 contain starch grains resembling those of the cortex. 



(4) Wood, traversed by medullary rays one cell wide. The wood 

 bundles consist chiefly of wood fibres with which are associated 

 scattered pitted vessels and wood parenchyma. The cells of the 

 latter, like those of the medullary rays, are distinguished by 

 containing starch grains and colouring matter. 



The diagnostic characters of powdered rhatany root are : 



(a) The reddish-broicn colour. 



(b) The characteristic starch grains, 



(c) The bast fibres. 



(d) The crystals of calcium oxalate. 



