CLASSIFICATION OF ANGIOSPERMS. 703 



FIG. 391. Buttonbush (Cephalanthus occidentalis) , a small shrub growing in swamps 

 and along streams throughout the United States. The leaves are opposite or whorled in 

 threes. The flowers are white and densely aggregated in spherical peduncled heads; they 

 secrete large quantities of nectar, and are sought to such a degree by the bees that the 

 bush is often called "Honey balls." After Troth. 



in its roots. The root is known commercially as MADDER, and con- 

 tains when fresh a yellow coloring principle, which on the drying 

 of the root breaks up into several glucosides, one of which on 

 further decomposition yields ALIZARIN, the principle to which the 



