198 CONVOLVULACEJB. 



Officinal Plants. 



Chironia centarium. 

 Gentiana lutea. 

 Menyanthes trifoliata. 



35. CONVOLVULACK.fi. 



Calyx monosepalous, its divisions 5, imbricated. 

 Corolla monopetalous, hypogynous, regular, deciduous ; 

 its limb 5-lobed and plaited. Stamens 5, placed upon 

 the base of the corolla, and alternating with its 

 divisions. Ovarium 2-4-celled, seldom imperfectly uni- 

 locular, the ovules definite and erect ; when more than 

 one in each cell, they are collateral ; style one, divided 

 at the top, or even to the base ; stigmas obtuse or 

 acute. Disk annular and hypogynous. Fruit cap- 

 sular, 1-4-celled, the valves corresponding at their edges 

 to the margins of a free dissepiment, in general with a 

 septicidal dehiscence, but occasionally opening trans- 

 versely. Seeds with but little albumen, which is muci- 

 laginous, the embryo curved, radicle inferior, and the 

 cotyledons shrivelled. 



Herbs or shrubs often twining, covered with a simple 

 down, and having lactescent juices. The leaves are 

 exstipulate and alternate, and the pedicels of the inflo- 

 rescence have two bractese. 



Geographical Relations. Decidedly equatorial plants, 

 though a few are found in Europe and North America. 



Properties. " These plants afford a good illustration 

 of the changes wrought in the properties of the vegeta- 

 bles by time, and of the necessity of age to elaborate 

 their peculiar and characteristic principles ; for the 



