216 



IMPORTANT FAMILIES OF PLANTS 



SUNFLOWER OR COMPOSITE FAMILY ( COMPOSITE) 



This is one of the largest families of the flowering plants. 

 It is characterized by numerous small flowers growing in a close 

 head. These flowers are either polygamous or monoecious. The 

 ovary is inferior and the calyx tube is attached to it ; the corolla 

 is five cleft, either tubular or strap-shaped ; stamens five, attach- 

 ed to corolla; anthers united into a tube surrounding the two- 

 cleft style. In most plants the central or disk flowers are 



FIG. 140. Sunflower, showing the composite flower head. 



tubular and the marginal flower strap-shaped, but in some 

 plants all of the flowers are of the same kind. 



This family includes some few plants used for food, such 

 as the Jerusalem artichoke (Helianthus tuberosus L.), lettuce 

 (Lactuca sativa), some few others that are used in medicines, 

 and a large number that are used for ornamental purposes, 

 such as the sunflower (Helwnthus annuus) (Fig. 140), the 

 daisy and chrysanthemum (Chrysanthemum carineum), gold- 

 enrods (Solidagos), asters, dahlias and others. 



