G2 



IPOMQSA HORSF ALLIES. 



The genus Ipomoea contains a great number of species, of which upwards of 

 160 have been described. They are for the most part tropical plants, remarkable 

 for their generally twining habit, and the beauty of their flowers. As striking 

 ornaments of the forest in their native country, they could not fail to arrest the 

 attention of the traveller ; many of them, consequently, have long been favourite 

 objects of culture in the stove, which they continue to adorn, if well managed, 

 with a daily and long-continued succession of flowers. 



Ipomoea is closely allied to Convolvulus, from which it differs in its usually 

 funnel-shaped (not bell-shaped) corolla; in the capsule being most frequently 

 three-celled instead of two-celled ; • and particularly in its globoso-capitate stigmas. 

 Convolvulus, as a well-known genus, has been selected as the type of a distinct 

 and well-marked natural order, the Convolvulace^: or Bindweed tribe ; the most 

 striking features of which are, the plaited corolla, the imbricated calyx, and 

 climbing habit. In this natural order are comprised about twenty-six genera, 

 agreeing with Convolvulus in the above, and certain other important characters. 

 They are all remarkable for the abundance of milky juice contained in their roots, 

 which, in different species, is more or less acrid in taste, and more or less purgative 

 in quality. This property is found to depend upon a peculiar resin, which is the 

 active principle of Jalap, Scammony, and the other valuable medicines obtained 

 from this tribe of plants. From Ipomoea jalapa, a native of Mexico, in the 

 neighbourhood of Xalapa (whence probably its name) is obtained the well-known 

 Jalap : Convolvulus scammonia produces the drastic purgative scammony. This 

 resinous principle exists in such minute quantity in some of the fleshy and mucila- 

 ginous roots, that they are used as wholesome and agreeable articles of diet. 

 Such is the Convolvulus edulis among the Japanese ; and the Convolvulus batatas 

 in all the tropical climates. The tubers of the latter were formerly imported into 

 this country as a delicacy under the name of the Sweet Potato. This is the potato 

 to which Shakspeare alludes in the " Merry Wives of Windsor the common 

 potato, Solarium tuberosum, being unknown in Europe previous to the reign of 

 Elizabeth. 



Our drawing was made from a beautiful specimen communicated by John 

 Willmore, Esq., of Oldford. 



Fig. 1, stamen, with its gland at the base ; 2, germ, with its style and two- 

 lobed capitate stigma. 



