28O 



PLANT FAMILIES: DICOTYLEDONS. 



The floral formula for the composite family then is as follows: 

 o5, A5, G2. 



Fig. 240. 



Ray flower of Aster 

 novae-angliae. 



Fig. 241. Fig. 242. Fig. 243. 



Tubular flower Tubular flower Syngenecious 



of aster. opened to show syn- stamens opened to 



genecious stamens. show style and two 

 stigmas. 



442, Other composites. The rattlesnake-weed (Hieracium 

 venosum) is an example of another type, with only one kind 

 of flower in the head, the true ligulate flower. The hawk- 

 weed, or devil's paint-brush (H. aurantia- 

 cum) is a related species, which is a 

 troublesome weed. The dandelion and 

 prickly lettuce are also members of the 

 ligulate-flowered composites. A number of 

 the composites have only tubular flowers, as 

 in the thorough wort (eupatorium) and ever- 

 lasting (antennaria). 



443. The composites are the most highly developed plants. 

 The extent to which the union of the parts of the flower has 

 been carried in the composites, and the close aggregation of 

 the flowers in a head, represent the highest stage of evolution 

 reached by the flowers of the angiosperms. 



Fig. 244. 



Diagram of composite 

 flower. (Vines.) 



