208 BARKS. 



(102) Simarouba Bark. 



The root bark of Simarouba officinalis, D.C. (N.O. Rutacese). 

 The bark presents the following structure : 



(1) Cork, if present, consisting of brown, flattened, tabular 

 -cells. 



(2) Cortex, composed of irregular, tangentially elongated, 

 polygonal cells, and containing resin cells and rather large 

 sclerenchymatous cells either isolated or in groups ; these cells 

 are very irregular in shape and have rather thick, lignified 

 walls. The cortex also contains an abundance of prismatic or 

 rhombohedral crystals of calcium oxalate. 



(3) Bast Ring, comprising the major part of the bark and 

 traversed by numerous medullary rays which are mostly two to 

 four cells wide and widen somewhat abruptly towards the 

 cortex. The bast rays contain numerous bast fibres arranged 

 in tangential bands which alternate with thicker tangential 

 bands of bast parenchyma and sieve tubes. The bast fibres are 

 often accompanied by groups of sclerenchymatous cells. The 

 individual fibres are rather large, irregularly flattened, and 

 provided with moderately thick, lignified walls. The bast rays 

 are also rich in prismatic crystals of calcium oxalate. The 

 number of sclerenchymatous cells and of crystals varies, how- 

 ever, greatly in different samples of bark. 



The diagnostic characters of simarouba bark are : 



(a) The characteristic bast fibres. 



(b) The sclerenchymatous cells. 



(c) The crystals of calcium oxalate in the cortical 



parenchyma. 



