MB. D< HANBUET ON A SPECIES OF IPOMCEA. 279 



II. mollis, M^i//rf. = Wigandia caracasana, H., B. et K. 

 n. scorjHoides, iVfoc. i»erf. = Wigandia scorpioides, Chois. 

 H. tenella, ilfoc. inec/. = Nama oiiganifolia, H., B. ef K. 

 H. violacea, ilfoc. inerf. = Nama longiflora, Chois. 



EXPLICATIO TABULA I. 



Fig. 1. Hydrolca ^pino^a (Linn.). Ovarium et styli. 



2. „ „ Sepala, capsula et styli (var. trigyna), 



3. „ „ Corolla et stamina. 



4. ,, ,, Semen. 



^' n elega'iis (nob.). Sepala, capsula, et styli. 



6. „ „ Semen. 



7. „ nigricaulis^ Griseb. Sepala et capsula. 



8. „ glabra (Schum.). Sepala et capsula. 



^- » zeylanica (Vahl). Sepala et alabastrum (forma glabrio 



10' » „ Sepala, capsula et styli (forma glandulosior). 



11- jj multiflora {(S\io\%^, Sepala et capsula. 



!*-• n grami?iifolia {noh,), Sepala et alabastrum. 



13. ,> macrosepala (nob.). Sepala circa fructum porciisteutia. 



/ 



Ou a Species of Ipomos^, affording Tampico Jalap. 

 By Dajs^xel Hajs^bukt, Esq., F.E.S., F.L.S. 



(Plate II.) 

 [Bead December 16, 1869.] 



Two centuries and a half have elapsed since Jalap, the tubercule 

 of a convolvulaceous plant of Mexico, was introduced into the 

 Materia Medica of Europe. The botanical origin of the drug long 

 remained unsettled, evidence of which exists in the fact that two 

 plants, neither of which yields jalap, have in succession received, 

 and still retain, the specific name Jalapa. The veritable source of 

 jalap, however, was brought to light between the years 1827 and 

 1S30, in which latter the plant was described by Wenderoth as 

 Convolvulus Pur^a. In 1833 it was figured by Hayne under the 

 name oilpomcea Purga ; but in 1839 it was transferred, on account 

 of its tubular corolla and exsert stamens, to Choisy's genus Exo~ 

 gonium. As this genus has been recently united to Ipomoea by 

 Dr. Meisner, it appears best to retui*n to the name proposed by 

 Hayne, and to call the true jalap-plant Ipomoea Furga. 



The unsettled condition ofMexico, andthe fluctuations of com- 

 merce, have alternately depreciated or enhanced the value of jalap, 

 aud have led to the occasional importation of other roots possess- 

 ing uiore or less of the characters of the true drug. Of such kinds 



