CLASSIFICATION OF ANGIOSPERMS. 247 



The root-stocks of a number of Orchids are rich in mucilage 

 and yield the drug salep or a product resembling it. Salep occurs 

 in the form of globular or somewhat flattened, more or less trans- 

 lucent, light yellowish-brown tubers, 2 to 4 cm. long,, of a horny 

 texture and a mucilaginous taste. The principal constituent is 

 mucilage which originates in the cell-contents. It may contain 

 in addition either starch or susrar. 



B. CLASS DICOTYLEDONS. 



The following are some of the prominent features of the Di- 

 cotyledons : (i) The leaves are reticulately (open) veined and 

 usually with an irregular margin, being sometimes deeply lobed ; 

 (2) the parts of the flower are usually in circles of 2 to 5 each ; (3) 

 the stems and roots generally increase in thickness by means of 

 a cambium, and the vascular bundles are open, varying from 

 simple collateral to bi-collateral ; annular rings are formed in the 

 perennial stems ; (4) the germinating plant usually has two 

 cotyledons which are opposite each other. The Dicotyledons are 

 divided into two series or sub-classes, depending upon whether 

 the parts of the corolla are distinct or are united, namely, the 

 Archichlamydese and Metachlamydeae. 



archichlamyde;e or CHORIPETAL^. 



The Archichlamydese or Choripetalae comprise those dicoty- 

 ledonous plants in which the petals are separate and distinct from 

 one another or are entirely wanting. 



1. ORDER PIPERALES. 



The plants of this order are mostly tropical herbs and shrubs 

 and possess very small flowers which have neither petals nor 

 sepals. The leaves are simple and without stipules, the most 

 important family medicinally as well as in other ways being the 

 PiPERACE.E, to which the following medicinal plants belong. 



Piper nigrum is a woody climber that has leathery, grayish- 

 green, ovate, cordate or Dvate-elliptical leaves, with three prom- 



