270 RHIZOMES AND HOOTS. 



130) Zedoary Rhizome. 



The rhizome of Curcuma Zedoaria, Roscoe (N.O. Scitamineee), 

 The rhizome presents the following structure : 



(1) Epidermis, the cells of which are flattened in transverse 

 section, but in surface view are rather large ; sometimes they are 

 polygonal and isodiametric, sometimes axially elongated ; the 

 walls are thin. Here and there rounded cells with thickened 

 pitted walls are to be found ; these are the bases of large, uni- 

 cellular, conical hairs, which 'have been broken oft. 



(2) Hypoderma, which is often absent. 



(3) Cork, usually of considerable extent ; the cells are large r 

 and, in surface view, appear polygonal. 



(4) Cortex, comparatively narrow and traversed by small fibro- 

 vascular bundles, some of which are accompanied by yellowish 

 thin-walled fibres. The cells of the cortical parenchyma are 

 mostly polygonal or rounded and contain starch, but a few 

 contain yellowish oleoresin. The starch grains are large and 

 simple, strongly flattened, and generally ovoid or sack-shaped ; 

 the hilum is close to the pointed end, and many grains exhibit 

 distinct striations. They are considerably larger than either 

 ginger or galangal starch. 



(5) Endodermis, the cells of which are flattened and not 

 lignified, 



(6) Stele, of large dimensions ; the parenchymatous tissue 

 resembles that of the cortex. 



The diagnostic characters are 



(a) The starch grains. 



(b) The epidermis with scars of hairs. 



(c) The oleoresin cells. 



(d) The abundant, thin-walled parenchyma. 



