CURCUMA. TURMERIC. I37 



thick- walled, mostly single-celled, blunt-pointed tri- 

 chomes, and here and there stoma ta. Oil cells are of 

 occasional occurrence. More numerous are the elon- 

 gated resin cells. The larger portion of the parenchyma 

 is well filled with starch, which by the scalding swells up 

 to form pasty masses which retain the form of the en- 

 closing cell even in the powder. The grains in their 

 natural form are small, 15 to 30 microns long, oval, tri- 

 angular, or three-^ided, sometimes long and thin or disc- 

 shaped. The concentric rings are visible but indistinct. 

 The hilum is at the smaller end. Here and there through- 

 out the bark are isolated irregular fibro-vascular bundles, 

 the numerous small angular sieve tubes surrounding the 

 rather large-celled vessel portion. Occasionally in the 

 parenchyma are found very small angular crystals of 

 calcium oxalate. 



A distinct endoderm of tangentially elongated cells 

 separates the cortical from the inner portion of the 

 rhizome. The structure within is in general similar to 

 that of the outer portion. The fibro-vascular bundles, 

 however, are much more numerous, especially near the 

 endoderm, where they merge into one another. They are 

 usually concentric, as in the cortical tissue, but here and 

 there an isolated bundle shows a rudimentary bicollateral 

 structure. The vessels show markings between spiral 

 and net-formed. The sieve tubes are weak with distinct 

 sieve plates. The parenchyma is filled with starch. 

 Resin cells are frequent, oil cells less so. 



Powder. — The curcuma in powder is easily recognized 

 by its characteristic color, odor, and taste. It tinges 

 the saliva yellow. The united masses of starch grains 

 retaining the shape of their enclosing cells make up 

 the greater portion. Isolated grains, uninjured by heat, 

 are also met with. The tissue elements, cork, paren- 

 chyma, and ducts, are of no diagnostic value. The 

 absence of bast fibres is noteworthy. 



