EXPERIMENT STATION BULLETINS. 



379 



MORNING GLORY FAMILY. CONVOLVULACEAE. 



Cliiefly twning vines, often containing milky juice; a few cultivated for ornament, and one, the 

 sweet potato, for its edible roots; a number are leaflessjparasitic vines. 



A rather large family including 900 species, mostly native to the tropics. 



Fig. 161 (141). 



Black Swallow-wort. Cynanchum nigrum 

 (L.) Pers. {Vincetoxicum nigrum Moench.) A 

 rather neat, smooth, dark green perennial 

 twining vine; 60-150 long; leaves narrow; 

 flowers small, dark purple; pods about 5 cm. 

 long. 



Introduced from Europe and a pest in land 

 not cultivated. 



(Fig. 161 belongs to the Milkweed family.) 



Fig. 162 (142). 



Small Bindweed. Convolvulus arvensis L. 

 A smooth, slender, prostrate or twining vine 

 from deep, widely spreading, perennial, fleshy 

 roots; leaves arrow or halberd shaped, 2-3 cm. 

 long; flowers bell shaped, seldom abundant, 

 white or tinged with pink, 1.5-2 cm. long. 



A very persistent weed when growing in 

 sandy land. Introduced from Europe. 



Otner names sometimes used; Hedge-bells, 

 Bearbind, Bellbine, Corn-bind, Lap-love, Sheep- 

 bine. 



Very troublesome in sand or gravel. 



