Solan ALES.] 



CONVOLVULACE.E. 



G3i 



Vei'y abundant in all parts of the tropics, but rare iu cold climates, wbei*e a few only 

 are found ; they twine round other shrubs, or creep among the weeds of the sea-shore. 

 In the coldest climates they are unknown. 



Their roots abound in an acrid milky juice, which is strongly purgative ; this quality 

 depends upon a peculiar resin, which is the active principle of Jalap, Scammony, and 

 others whose roots possess similar qualities. Scammony is exclusively furnished by 

 Convoh"ulus Scammonia, a Syrian perennial ; and a similar drastic substance is 

 obtained from Ipomoea tuberosa, the Spanish Arbour Vine of Jamaica, Pharbitia 

 cathartica, a St. Domingo plant, two Brazilian species called by Martins Piptostegia 

 Gomezii and Pisonis, and others. Of Jalap the best sort is obtained from Exogonium 

 Purga, a beautiful twiner with long crimson flowers ; but other species are also col- 

 lected under the same name. Mr. Hartweg ascertamed that Ipomoea Batatoides is the 

 Purga Macho or Male Jalap of Mestitlan. Convolvulus Arvensis, Soldanella, mari- 

 timus, macrocarpus, and probably many others, may be used with nearly equal advan- 

 tage. The root of Convoh^ulus pandui'atus is employed in the United States as Jalap ; 

 its operation is like that of Rhubarb ; it is supposed to be also diuretic. The roots 

 of Rhodorhiza florida and scoparia, and Ipomoea Quamoclit, are used as sternu- 

 tatories ; those of Batatas eduHs and others are useful articles of food ; the former is the 

 common Sweet Potato of Em'opean gardens. Convohnalus dissectus abounds in pinissic 

 acid, and is one of the plants from which the liquem' Noyau is prepared. — Bot. Mag. 

 3141. The Ipomoea sensitiva of Tm*pin is remarkable for the irritabihty of its corolla. 

 A sort of Jalap having the odour of Roses is described by Guibom-t in the Pharm. 

 Journ. 3. 331. It is not known from what species of this Order it has been obtained. 

 Ipomoea operculata yields a purgative drug, imported into Em-ope vmder the name of 

 Gomma da Batata ; and a long list might be made of other species whose purga- 

 tive quaUtes have been ascertained. Among these, the foUomng deserve principal 

 mention : Ipomoea pandm'ata, or Mechamek, an American plant ; Ipomoea Turpethum, 

 common in the East Indies, Malayan Archipelago, New Holland, Timor, Otaheite, 

 Friendly Islands, Marianne Islands, Tinian, &c. ; Convolvulus althaeoides, a beautiful 

 Mediterranean plant ; and the Calystegias sepium and Soldanella, common in this 

 country. Nevertheless, the purgative resin is hardly present in certain species, where 

 it is replaced by starch or sugar ; as in Batatas edulis, the common Sweet Potato, 

 whose root is an important article of food in tropical countries, and Batatas jalapa, 

 which was formerly called Ipomoea macrorhiza, and, notwithstanding the fonnidable 

 name first quoted, is inert ; it is a plant inliabiting the sandy soil of Georgia and Caro- 

 lina, with white insipid farinaceous roots weighing from 40 to 50 lbs., and is asserted 

 by EUiot (Sketch i. 253.), to possess no purgative properties whatever. Dr. Baldwin 

 assured him that he had administered 6 drachms of the powdered root without effect, 

 and that in fact it contains little or no resin, but Uke the Batatas eduhs consists chiefly 

 of saccharine and farinaceous matter. Of some the seeds partake m the purgative 

 quahties of the roots. The seeds of the Kaladana or Pharbitis cserulea act as a quick, 

 safe, and pleasant cathartic in doses of 30 to 40 grains. In some the leaves are 

 emollient. A decoction of the leaves of Argyreia bracteata is used by the natives of 

 India as a fomentation in cases of scrofulous enlargements of the joints ; the boiled 

 leaves being employed as a poultice at the same time. And the foliage of Ipomoea 

 maritima is employed in Brazil in a similar manner. The species of Rhodorhiza yield 

 by distillation an essential oil of a bitter balsamic flavour, called Oil of Rhodium ; 

 they are not, however, according to Mr. Barker Webb, the puZia pi^a of Dioscorides, 

 which he thinks was certainly Rhodiola rosea. The wood when powdered has been 

 recommended to promote sneezing, and forms an agreeable snuff ; it is valued for fumi- 

 gation, and when burned diffuses a delightful fragrance. According to a Dr. Uslar, 

 of Oaxaca, the poison called in Mexico Guaco is a Convohnilus. 



GENERA. 



I. CONVOLVULK^. — 



Carpels consolidated. 



Wilsonia, R. Br. 

 Stylisma, Raf. 

 Evolvnlus, Linn. 



Cladostyles, H. B. K. 



Meriana, Flor. Flum. 

 Cressa, Linn. 

 Breweria, R. Br. 

 Seddera, Steud. el Hoch. 

 Dufourea, Kunth, 



Prevostea, Chois. 



Dethardingia, Nees. 



I Reimvardtia, Spreng. 



Calycobolus, Willd. 

 Bonamia, Thouars. 

 Neuropeltis, Wall. 

 Porana, Burm. 



Dinetus, Sweet. 

 Duperreya, Gaudich. 

 Palmia, Endl. 



Hewittia, Wight. 



Shutereia, Chois. 

 Skinneria, Chois. 

 Polymeria, Linn. 

 Calystegia, R. Br. 



Aniseia, Chois. 

 Convolvulus, Linn. 

 Merremia, Dennst. 

 Rhodorhiza, Wehh. 

 Jacquemontia, Chois. 

 Exogonium, Chois. 

 Lepistemon, Blum. 

 Calonyction, Chois. 



Bonano.v, llaf. 

 Ipomoea, L. 



Piptostegia, Iloffms. 



Lcjitocallis, Don. 



Elijlroslamina, Boj. 



. Mina, Llav. 



I (iuamoclit, Tournef. 



' Calboa, Cav. 



Macrostcma, Pers. 

 Morenoa, Llav. et Le.\. 

 Batatas, Chois. 

 Ojk-rculiua, Manso. 

 Boiiibi/cosjk-rniiim , Prl. 

 Spiranlhera, Boj. 

 Pharbitis, Chois. 



CowolniloidiS, yionch. 

 Rivea, Chois. 

 Argyreia, Lour. 



