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 sugar. 



B. CLASS DICOTYLEDONS. 



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

 cotyledons; (1) 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 stem is usually differentiated into pith, wood and bark and the 

 fibrovascular bundles are of the open collateral type, arranged 

 radially about the pith and separated from each other by medul- 

 lary rays; (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 Archichlamy- 

 deas and Metachlamydeas. 



ARCHICHLAMYDE^ OR CHORIPETAL^. 



The Archichlamydeae or Choripetalse comprise those dicoty- 

 ledonous plants in which the petals are separate and distinct from 

 one another or are entirely wanting. 



I. 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^, to which the following medicinal plants belong. 



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

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



