Tab. 4280. 
EXOGONIUM PuRGA. 
Vurga, or True Jalap. 
Gen. Char. Sepala quinque. Corolla tubulosa. Stamina exserta. Stylus 1, 
Stigma capitatum, bilobiun. Ovarium biloculare, locuKs biovulatis. Chois. 
Exogonium Purga ; foliis cordatis acuminatis integerriims utrinque glabris, 
pedunculis 2-3-floris, tubo coroEae calycem obtusum quadruple superante, 
limbo hypocraterimorpho, lobis obtusis subemarginatis. Chois. 
Exogonium Purga. Benth. PI. Kart.p. 46, andPi. dumosum,* egusd. 
Ipomcea Purga. Wenderoth, PI. Central, v. 1. p. 457. Choisy, in DC. Prodr. vM, 
p. 374. Bindley, Flor. Med. no. 809. Bot.Reg. Misc. 1839, n. 836. Nees 
ah Esenbeck, PI. Off. Stippl. v. 3. 1. 13. Hayne, Darstell. undBeschreib. Arz- 
neikundgebraiechlich PJlanzen, 1833, t. 33, 34. 
IpoMCEA Sebiedeana. Zuccarsini, Abhand. de Bagn. Acad, du Wissenschaft. 1832. 
Ipomcea Jalapa. Nutt, and Core, Amer. Journ. of Med. Science, Feb. 1830, t. 7. 
Boyle III. Him. p. 308 {non Pursh.). 
Convolvulus Jalapa. Schiede in Linneea, 1830, js. 473. {non Linn.) 
Although Jalap has been used in European medicine for nearly 
two centuries and a half, it is only within a few years that its 
botanical source has been correctly ascertained. The plant long 
cultivated as yielding the true Jalap, in the stoves of Europe, 
and among the rest in the Botanic Gardens of Edinburgh, is 
the Convolvulus Jalapa of Linnaeus and Willdenow, or Ipomoea 
macrorhiza, of Michaux, a native of Vera Cruz, But, between 
the years 1827 and 1830, it was proved by no fewer than three 
independent authorities, M. Ledanois, a French druggist, resi¬ 
dent at Orizaba, in Mexico, Dr. Coxe, of Philadelphia, through 
information supplied by Mr. Eontanges, an American gentleman, 
who lived at Jalapa, and Schiede, the botanical traveller, from 
personal examination, that the drug of commerce is obtained, not 
from the hot plains around Vera Cruz, but from the cooler hill 
country near Jalapa, about 6,000 feet above the level of the sea, 
where it is exposed to frost in winter-time; and that the plant 
* Choisy is no doubt right in referring Mr. Bentham’s E.dumosum to E. Purga; 
but surely wrong in transferring these plants from Exogonium (coroUa tubulosa, 
stamina exserta), to Ipojncea (coroEa campanulata, stamina inclusa!). 
FEBB.UARY IST, 1847. C 2 
