222 RHIZOMES AND ROOTS. 



(106) Calumba Root. 



The root of Jateorhiza Columba, Miers (N.O. Menispermaceae). 



p 



The root presents the following structure : 



(1) Cork, consisting of several rows of brown, tabular cell?, 

 which in surface view are polygonal and isodiametric. 



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

 tangentially elongated ; they contain large starch grains (20 to 

 lOp) which are mostly simple, irregularly ovoid, rounded or 

 pearshaped and exhibit a very conspicuous cleft or stellate 

 hilum. There are also compound grains with from two to six 

 constituent grains, measuring about 8-20//. in diameter ; theso 

 constituent grains are rounded on one side and angular on the 

 others. Towards the periphery the cortex contains large, scatter* d , 

 thicked-walled, sclerenchymatous cells either isolated or in 

 groups ; the cavities of these ceils are large and contain one or 

 more prismatic crystals of calcium oxalate ; the walls are 

 bright yellow in colour and often exhibit a one-sided thickening. 



(3) Bast Ring, containing very long and narrow bast rays 

 destitute of fibres. 



(4) Wood, largely composed of parenchyma, traversed by 

 scattered fibrovascular bundles. These bundles are narrow and 

 radially elongated ; they are composed of large pitted vessels 

 surrounded by a layer of more or less thickened but cnly very 

 slightly lignified fibrous cells. 



The diagnostic characters of powdered calumba root are : 



(a) The yellow colour of the sclerenchymatous cells and 



vessels. 



(b) The sclerenchymatous cells uith calcium oxalate 



crystals, 



(c) The characteristic starch grains. 



