1 88 



CONVOLVULACE^:. 



[CLASS 



The Order abounds in a bitter principle, and several 

 species are used in medicine. 



44. Natural Order Convolvulaceae. The Convolvulus 

 Family. , 



DISTRIBUTION. Chiefly tropical and sub-tropical, 

 both in the Old and New World. British genera 3, 

 species 6. 



Twining or creeping herbs. Calyx polysepalous. Corolla 

 regular, hypogynous, lobes plaited in bud. 



Type Field Bindweed (Convolvulus arvensis). 



A twining or prostrate herb, with alternate sagittate 

 leaves, and axillary pedunculate flowers with handsome 

 plaited corollas. 



OBSERVE the folded aestivation of the corolla : the 

 anomalous genus Dodder (Cuscuta), the species of which 

 are leafless twining parasites germinating in the soil, but 

 becoming attached to their prey (Furze, Clover, Flax, &c.) 

 at an early stage of growth, by suckers, which penetrate 

 the epidermis. The embryo of Dodder is filiform, coiled 

 up in the albumen, and destitute of cotyledons. In some 

 species rudimentary cotyledons are formed at one extremity 

 of the embryo. 



Sweet Potatoes, cultivated all over the Tropics, are the 



