THE BINDWEED FAMILY. 



295 



Batatas Jalapa. A native of Mexico, near Xalapa, from 

 whence it takes its name. It has large farinaceous roots, 

 which are of a purgative nature, but although called Jalap, 

 it is not the plant which yields the true drug of that name, 

 which is produced by Exogonium Purga, a native of the 

 higher regions of Mexico. The roots are round, of various 

 sizes, and contain a resinous secretion, which is the strong 

 purgative Jalap used in medicine. 



Iipomcea tuberosa. A native of Jamaica, and often grown in 

 greenhouses in this country ; it also has purgative qualities. 



Scammony (^Convolvulus Scammonia). A long thick 

 tuberous-rooted herbaceous plant, native of Western Asia. 

 Scammony is obtained by cutting off the top of the root at 

 the surface of the ground, when a milky juice exudes which, 

 after becoming hard, is collected. It comes to this country 

 from Aleppo and is used as a purgative medicine. An in- 

 ferior kind, believed to be the produce of Periploca Scam- 

 monium, comes from Smyrna. 



Oil of Ehodium (Convolvulus Scoparius and C. fioridus). 

 Two small erect, branching shrubby species with small silky 

 leaves and white-and-pink flowers, natives of the Canary 

 Islands. On account of the scent their wood is called " rose- 

 wood," from which an oil is extracted which is used in adul- 

 terating attar of roses. The wood is now very rare. 



Convolvulus dissectus. A tropical species cultivated in 

 France. It abounds in prussic acid, and is used in making 

 the liqueur called noyeau. 



Many of the species of this family form very ornamental 

 creepers in hothouses, but to have them in perfection they 

 require much space. A number of years ago a plant at Kew 

 of Ipomcea mutabilis covered a space of 150 square feet, and 

 during the flowering season 200 of its beautiful blue flowers 

 have been counted open at the same time. 



Ipomcea bona-nox. An annual, native of the East Indies. 

 It has large flowers 5 to 6 inches in diameter, which being 

 pure white have a remarkable appearance at night, and has 

 led to the name of "moon flower" being applied to it. 



