186 EXOGONIUM PURGA 



the base of the tube, filaments somewhat flattened, 3 longer than 

 the other two, all somewhat exserted beyond the throat of the 

 corolla and towards one side, anthers small, introrse. Ovary 

 tapering into the slender style which extends a very little beyond 

 the stamens, 2 -celled, surrounded by an annular disk ; stigma of 

 two rounded papillose lobes ; ovules 2 in each shell. Fruit not 

 seen. 



Habitat. This grows in damp, rich, shady woods in the moun- 

 tainous country near Jalapa* in West Mexico, at an elevation of 

 about 6000 feet above sea level. It was introduced into the Edin- 

 burgh Botanic garden in 1838, and is now to be met with pretty 

 generally. As an ornamental plant it has considerable claims to 

 notice, being easily propagated and flowering in the open air with 

 but slight shelter from September till checked by the first frosts. 

 It is not, however, able to ripen its fruit here, nor have we met 

 with any description of it. The tubercles are hypertrophied roots, 

 and are usually accompanied by ordinary fibrous ones and often 

 by some intermediate in character. Subterranean white horizontal 

 shoots are also given off from the crown of the tubercles. 



Choisy, the monographer of the Convolvulacete, places this in 

 Ipomcea, but the long corolla tube and exserted stamens are at 

 variance with the characters of that genus as given by him. 



D. Hanbury has described and figured (Journ. Linn. Soc., 

 Bot. xi, p. 279, t. 2), under the name of Ipomtea simulans, the 

 plant which yields the Jalap of Tampico, a coast town of Mexico, 

 north of Jalapa. Another sort called Orizaba root, from the place 

 of that name, is the produce of I. orizabensis, Ledanois. 



Choisy, in DC. Prod., ix, p. 374 ; Balfour, in Bot. Mag., t. 4280 

 Lindl., Pi. Med., p. 396. 



Official Part and Name. JALAPA ; the dried tubercules (B. P.). 

 The dried tubercules (Jalapa) (I. P.). JALAPA; the tuber 

 (U. S. P.). 



Collection and Commerce. In Mexico, whence the official jalap 

 is obtained, the tubercules are dug up, to some extent, during the 



* Whence the drug gets its name of Jalap. 



