444 BOTANY AND PHARMACOGNOSY. 



exist in greatest amount in the cortical portion, and the periderm 

 serves to prevent the volatilization as well as deterioration of these 

 principles. 



Rhizomes are distinguished as upright, horizontal or oblique, 

 depending upon their manner of growth, and this may be deter- 

 mined in the drug by placing the rhizome in such a position that 

 the stem-scars are horizontal. 



I. True Roots. 



1. Monocotyledons Sarsaparilla 



2. Dicotyledons. 



A. Periderm removed Althaea 



B. Periderm present. 



a. Roots nearly entire. 



Tuber-like Jalapa 



Long, thin and of a reddish color Krameria 



Fusiform, very acrid Pyrethrum 



Keeled, crown knotty Senega 



Fusiform, small, yellowish central wood. .Taraxacum 



b. Roots cut into transverse pieces. 



Yellowish-green disks Calumba 



Concentric zones of collateral fibrovascular 



bundles Pareira 



Bark soft, spongy and finely fibrous Stillingia 



Very light in weight, wood large with 



fibers interlacing Sumbul 



c. Roots cut into longitudinal pieces. 



Characteristic odor and taste Belladonnae Radix 



Horny, tough, pith white Lappa 



Ribbon-like slices, very fibrous Phytolacca 



d. Roots more or less broken into pieces. 



Bark transversely fissured and easily 

 separable from the wood Apocynum 



Somewhat tortuous, bark irregularly 

 annulate and sometimes transversely 

 fissured Ipecacuanha 



II. Rhizomes that are Root-like. 



A. Periderm removed. 



Yellowish, fibrous, taste sweetish Glycyrrhiza (Russian) 



Reddish-brown, heavy, granular Rheum 



