Composite? Cen ta u rea. 



261 



the countries bordering the Mediterranean Sea. G. nigra, 

 Knapweed or Buttonweed, is a familiar native example. The 

 name is of classical origin. We must limit ourselves to a small 

 selection. 



Annual Species. 



1. C. Cyanus. Cornflower.-^This handsome species is com- 

 monly seen in our corn-fields, where its bright blue flower- 

 heads are highly attractive. It grows from 2 to 3 feet high, 

 bearing numerous terminal stalked flower-heads. Leaves 

 linear, entire or lobed, cottony. Under cultivation this species 

 has produced white, pink, and purple varieties. 



2. C. Americana (fig. 149). A very ornamental species, 



Fig. 14y. Ceutaurea Americana, 

 (i URt. size.) 



nat. size.) 



about 3 or 4 feet high. Flower-heads very large, lilac-purple, 

 A native of the southern United States. 



