CONVOLVULUS. 103 



beating rains and violent winds ; but light spring or sum- 

 mer showers will refresh them. 



This genus furnishes to the materia medica two of its 

 most powerful drugs : scammony, from a species growing 

 naturally at the Levant; and jalap, from another kind, 

 which is a native of Xalapa, between Vera Cruz and 

 Mexico. They are obtained from the roots of the plants. 

 Most of these flowers close at night; and many remain 

 close all day when the weather is wet or cloudy, but open 

 to the sunshine : 



" Qual' i fioretti dal notturno gielo 

 Chinati e chiusi, poi che '1 sol gl' imbianca. 

 Si drizzan tutti aperti in loro stelo." 



Dante, Inferno, Canto II. 



" Like flow'rs, which shrinking from the chilly night. 

 Droop and shut up ; but with fair morning's touch 

 Rise on their stems, all open and upright." 



COEEOPSIS. 



CORYMBIFERiE. SYNGENESIA POLYGAMIA FRUSTANE^E. 



The generic name is from the Greek, bug-like, the seed being like 

 a bug or tick : hence it is called by gardeners the Tick-seeded Sun- 

 flower. 



The Whorl-leaved Coreopsis has a yellow flower with 

 a purple centre: it is a showy plant, grows very tall, 

 and continues long in flower. It begins to blossom in 

 July. It is a native of North America, where the flowers, 

 although yellow, are used to dye cloth red. 



The Three-leaved has the same coloured flowers, and 

 is from the same country. 



