SENNA LEAVES. 317 



Ipomcea and Convolvulus chiefly by the stamens being pro- 

 truded out of the tube of the corolla. It is a beautiful 

 climbing convolvulus-like plant, with delicate pink flowers ; 

 its stem is perennial, but very thin, and forms in the ground 

 a tuber of an oval figure thin at each extremity, where the 

 stem and roots are given off; it reaches the size of a small 

 turnip, but the largest tubers are rarely selected ; they be- 

 come much smaller by drying ; externally the tubers are of 

 a dark umber-brown colour and much wrinkled. The im- 

 ports are nearly 150 tons per annum. A spurious kind of 

 jalap is often found in the markets under the name of 

 Male-jalap, or He-jalap ; it consists evidently of pieces of 

 a much larger tuber, much coarser, but in general appear- 

 ance not unlike the true species ; it is produced by Ipomcea 

 Orizabensis (Convolvulacece) . 



Senna Leaves. — Dried leaves of several species of 

 Cassia (Nat. Ord. Leguminosce). 



There are several qualities of Senna in commerce, and it 

 is thought they are all derived from different species. The 

 principal commercial kinds are Aleppo, Alexandrian, and East 

 Indian or Tinnevelly Senna. They are supposed to be yielded 

 by the following species : — Aleppo, by Cassia obovata, a per- 

 ennial herbaceous plant, a native of Northern Africa, but 



