72 SARSAPARILLA. 



its woody portion which is composed of fibro-vascular bun- 

 dles, is found near the central part, surrounded by a brown ring 

 or nucleus sheath, see A figure 2. Within this nucleus sheath 

 the bundles are so densely packed as to form a woody zone. 

 The very centre of the section consists of white pith. Occa- 

 sionally an isolated fibro-vascular bundle will be found. Out- 

 side the nucleus sheath we find the same structure as the pith> 

 simple parenchyma. There is no bark proper, but in its place 



Fig. 2. Microscopic Section of Sarsaparilla root. 



a thin epidermis of tabular cells. In a longitudinal section 

 the fibro-vascular bundles are found to consist of large scalari- 

 form vessels and long thick-walled cells, called prosenchyma. 

 In two of the varieties of sarsaparilla the parenchyma of the 

 pith and all the cells outside of the nucleus sheath are load- 

 ed with starch grains. These are large compound grains ., 1 , M> 

 of an inch in diameter. Some of the cells contain needle- 

 shaped crystals of calcium oxalate. In two varieties of sarsa- 

 parilla which do not contain starch, the prosenchyma and the 

 vessels contain a bright yellow resin. The principal structure 

 of interest in the whole texture of sarsaparilla is the brown 

 nucleus sheath seen at A, fig. 2. This little narrow row of 

 cells seems to be the guide by which the different varieties 

 are determined, for each cell is characteristic of the variety to 

 which it belongs. Each individual cell may be tabular and 



