122 THE STORY OF PLANT LIFE 



52. The Convolvulus Group. 



The Order Convolvulaceae is an extensive group, 

 consisting of a thousand species which are included 

 in forty genera. The species are mainly confined 

 to the warm and temperate regions. 



In the British Flora are included three species of 

 Convolvulus and three species of Dodder. 



These plants are principally perennial or annual 

 herbaceous plants or shrubs, usually twiners, but a 

 few are trees. Some lianes are included in the group, 

 and some are adapted to dry conditions. The Dodders 

 are parasitic climbing plants. Some of the members 

 of the group contain a milky juice. The leaves are 

 usually alternate and stalked. But in Dodder there 

 are no leaves. In a few cases there are stipules. 



The inflorescence is a cyme or a raceme, as a rule, 

 with bracts and bracteoles. The flowers are rarely 

 solitary. They are hermaphrodite, regular, hypo- 

 gynous, with the parts in fives. The calyx is poly- 

 sepalous, as a rule, inferior, with five distinct sepals, 

 often unequal, the odd sepal posterior, overlapping 

 in bud, persistent. The corolla is gamosepalous or 

 sympetalous, regular, deciduous, hypogynous, tubular, 

 bell-shaped, funnel-shaped, induplicate to valvate, or 

 twisted in bud, with four to five lobes, or sub-entire, 

 or angled. The stamens are five, inserted on the 

 tube, epipetalous on the base of the corolla, alternate 

 with the petals. 



The filaments are sometimes unequal, and swollen 



