MONOCOTYLEDONS AND DICOTYLEDONS 279 



head and exposed by the swab-like rising of the style (Fig. 

 263). The head is thus smeared with pollen, and visiting 

 insects can not fail to distribute it over the head or carry 

 it to some other head. 



In the dandelion and its allies the flowers of the disk 

 are like the ray-flowers, the corolla being zygomorphic and 

 strap-shaped (Figs. 262, 263). 



The combination of characters is sympetalous, tetracyc- 

 lic, and anisocarpic flowers, which are epigynous and often 

 zygomorphic, with stamens organized into a tube and calyx 

 modified into a pappus, and numerous flowers organized 

 into a compact involucrate head in which there is more or 

 less division of labor. There is no group of plants that 

 shows such high organization, and the Composite seem to 

 deserve the distinction of the highest family of the plant 

 kingdom. 



The well-known forms are too numerous to mention, 

 but among them, in addition to those already mentioned, 

 there are iron-weed (Vernonia), Aster, daisy (Bellis), 

 goldenrod (Solidago), rosin-weed and compass-plant (Silph- 

 ium), sunflower (Helianthus), Chrysanthemum, ragweed 

 {Ambrosia), cocklebur (Xanthium), ox-eye daisy (Leucan- 

 themian), tansy (Tanacetum), wormwood and sage-brush 

 (Artemisia), lettuce (Lactuca), etc. 



