CONVOLVULACE.E. BINDWEED TRIBE. 423 



in the north, but rare ; a common garden flower, not 

 easily rooted out where it has once established itself. 

 A tall, erect plant, 1 2 feet high, with an angular 

 stem ', pinnate, smooth leaves ; and numerous terminal, 

 large, blue or white flowers. Fl. June, July. Peren- 

 nial. 



ORD. LVIL COJSTVOLVULACKE. THE BINDWEED 

 TRIBE. 



Calyx in 5 divisions, imbricated, often very unequal, 

 not falling off ; corolla of one petal, regular, plaited ; 

 stamens 5, from the base of the corolla ; ovary 2 4- 

 celled, few-seeded, surrounded below by a fleshy ring; 

 style 1 ; stigmas 2 ; capsule 1 4-celled. An extensive 

 and highly valuable tribe of plants, most of which are 

 herbaceous climbers, with large and very beautiful 

 flowers. They are most abundant within the tropics, 

 where they are among the most ornamental? of climbing 

 plants. As medicines, also, they occupy an important 

 station. The roots of Convolvulus Scammonia, a Syrian 

 species, furnishes scammony ; jalap is prepared from a 

 resin which abounds in the roots of several kinds of 

 Exogonium, a beautiful climber, with long crimson 

 flowers ; and Convolvulus Batatas is no less valuable in 

 tropical countries, supplying the sweet potato, the roots 

 of which abound in starch and sugar, and are a nourish- 

 ing food. Cuscuta (Dodder) is a parasitic genus, with 

 branched, climbing, cord-like stems, no leaves, and 

 globular heads of small wax-like flowers. The seeds 

 germinate in the ground, and the young plants climb the 

 stems of adjoining plants ; and when they have taken 

 root in them, lose their connexion with the ground. 

 One British species is very abundant on the Furze ; 

 another on Flax, with the seeds of which it is supposed 

 to be introduced ; and a third grows on Thistles and 

 Nettles. 



