204 Dr Balfour's Description of Uarc Plants. 



3. Jacquemontia, stigmata ovate, flattened, stamens included. 



4. Tpomo^a, stigmata capitate-globose, stamens included. 



5. Exogoniuin, stigmata capitate-globose, stamens exserted. 

 Schiede found the plant at a great elevation on the eastern slope of 



the Mexican Andes, near Chieonquiaco ; and also on the eastern 

 slope of Cofre de Perote. He gives an account of his discovery 

 in the Linnfeafor 1830. Hartweg, it appears, lias also found the 

 plant in Mexico, and it has been described by Bentham from liis 

 specimens. 

 Altliough jalap has been used in European medicine for nearly two 

 centuries and a half, it is only within a few years that its bota- 

 nical source has been correctly ascertained. The plant long cul- 

 tivated as the true jalap-plant in the stoves of Europe, and, among 

 the rest, in the Botanic Garden of Edinburgh, is the Convolvulus 

 Jalapa of Linnfeus and Willdenow, or Ipomoea macrorhiza of 

 Michaux, a native of Vera Cruz. But between the years 1S27 

 and 1830, it was proved, by no fewer than three independent au- 

 thorities, M. Ledanois, a French druggist, resident at Orizaba in 

 Mexico ; Dr Coxe of Philadelphia, through information supplied 

 by M. Fontanges, an American gentleman who resided at Jalapa ; 

 and Schiede, the botanical traveller, from personal examination, 

 — that the root of commerce is obtained, not from the hot plains 

 around Vera Cruz, but from the cooler hill country near Jalapa, 

 above 6000 feet above the level of the sea, where it was exposed 

 to frost in the winter time; and that the plant which yields it, is 

 an entirely new species of the Convolvulaca;e. Schiede introduced 

 tlie plant fur tlie first time into Europe; and it has been cultiva- 

 ted in various botanic gardens of Germany. In this country it 

 was probably first cultivated in the Botanic Garden of Edin- 

 burgh, from a tuber sent by Dr Coxe of Philadelphia to Dr 

 Cbristison, in 1838. Dr Graham could not describe it at tliat time, 

 because, owing to unacquaintance with the habits of the plant, it 

 was forced in the stove, and died the same year, after forming nu- 

 merous flower-buds, of which one only became partially developed. 

 In lSi4, a plant from the Chelsea Botanic Garden, cultivated in 

 a cold frame in the Edinburgh garden during the winter and 

 spring, and uncovered in the summer and autumn, flowered 

 luxuriantly in September. But the crown of the tuber was in- 

 jured by frost in the subsequent winter, and the tuber was thus 

 killed. A di-awing was taken by Dr Graham, but it has not been 

 found among his papers. Ultimately, Mr IM'Nab resolved to try 

 whether the plant could bo raised from slips; and the experi- 

 ment has proved completely successful. A tuber, of the size of 

 a hazel-nut, formed in the course of three months. The stem 

 made little progress the next summer ; but when transferred to 



