474 



MEDICAL BOTANY. 



A very extensive genus, and one that has been ill-defined, and even now, 

 as exposed by Choisy, containing several species that may belong to other 

 genera. It is very closely allied to Convolvulus, .and resembles it in most 

 particulars. The largest proportion of the species are natives of warm 

 climates. Several among them have highly purgative roots, but they are by 

 no means uniform in their qualities. There are about 300 species described. 



I. purga, Wenderoth. — Leaves cordate, acuminate, entire, deeply sinuated at base, 

 smooth. Peduncles 1 — 2, rarely 3-flowered. Sepals obtuse. Corolla salver-shaped, with 

 a cylindrical tube. Stamens a little exserted. 



Wenderoth, Pharm. Centralb., i. 457 ; Lindley, Flor. Med. 396 ; Royle, 

 (1. jalapa,) III. Hymal., 308 ; J. R. Coze, (J. jalapa,) Am. Jour. Med. 

 Sci. 1830. 



Common Name. — Jalap Plant. 



Foreign Names. — Jalap, Ft, : Scialappa, It. 



Jalappenharz, Ger. 



Fig. 212. 



' Description. — Root roundisli or pear-shap- 

 ed, perennial ; tubers sending out long 

 radicles. Stems several, roundish, herba- 

 ceous, of a reddish-brown colour, much 

 twisted, smooth. Leaves cordate, entire, 

 smooth, conspicuously acuminate, and deeply 

 sinuated at base, the lower ones sometimes 

 almost hastate, the under surface promi- 

 nently veined, the footstalks often nearly 

 the length of the leaf. Peduncles about the 

 length of the petioles, two, rarely three- 

 flowered. Calyx ebracteate, five-parted, ob- 

 tuse, two of the divisions external. Corolla 

 salver-shaped, of a lilac-purple colour. 

 Stamens five. Anthers oblong, white, some- 

 what exserted. Ovary slender, bilocular. 

 Style slender. Stigma capitate. Seed not 

 known. 



The Jalap plant is found in Mexico, 

 at a considerable height above the 

 sea, and the roots are generally ex- 

 ported from Jalapa by way of Vera 

 Cruz. Until within a few years 

 there has existed much difference of 

 t. purga. opinion respecting the species of the 



Convolvulacese furnishing this valuable 

 purgative. 

 The first author who speaks of Jalap in a definite manner is G. Bauhin, 

 in 1609, (Pinax, 298,) under the name of Bryonia mechoacana nigricans. 

 Ray (Hist. Plant., 724) referred it to Convolvulus, as C. Americanus, jala- 

 pium dictus, in which he was followed by Plukenett (Phytog. Tab. f. 1). 

 Some time afterwards Tournefort, misled by Plumier and Lignon, who stated 

 that they had seen the plant in America, attributed the jalap to a species of 

 Mirabilis (Inst. Rei Herb., 130), and this erroneous idea was also adopted 

 by Lemery, in the second edition of his great work on drugs, where he figures 

 a Mirabilis as the jalap plant. (PI. VI. f. 13.) But Miller (Gard. Diet.), 

 and Sloane (Hist. Jam.), again referred it to Convolvulus, and their views 

 were confirmed by Houston, who brought the plant from South America and 

 showed it to Jussieu, who decided that it belonged to that genus. 



