408 CONVOLVULACE^. [part it. 



the little scarlet Ipomcea, the capsule is four- 

 celled, and the cells one-seeded ; the corolla is 

 tubular, and the stamens project beyond the 

 throat. Batatas, the Sweet-potato, resembles 

 Quamoclit, but the corolla is campanulate, and 

 the stamens are inclosed. In Pharbitis (in 

 which genus the common Convolvulus major, 

 and the beautiful Ipomcea Learii, are both now 

 included), the capsule is three-celled, and the 

 cells are three-seeded; and in Calystigia, in 

 which is now placed the common bindweed of 

 the hedges, the capsule is one-celled and four- 

 seeded ; and the flower, which in other respects 

 agrees with that of the genus Convolvulus, has 

 two bracts which serve as a sort of involucre. 

 All these flowers have the lobes of the corolla 

 marked with a decided fold or plait, and they 

 are climbing plants, generally annuals. Cuscuta 

 is a parasite belonging to Convolvulacese, which 

 though it springs from the ground, withers 

 just above the root as soon as it has twined 

 itself round any plant within its reach ; dr^,w- 

 ing its entire nourishment from the unfortu- 

 nate plant it has attacked, and which it soon 

 kills. The plants in this order produce an 

 acrid milk ; and the roots of a kind of Con- 

 volvulus yield the drug called Jalap, which 

 takes that name from the Mexican city Xalapa, 

 near which it is grown. 



