No. 439.] NOR THERN G A MOPE TA LCH r S FL OH ERS. 



445 



series. The individual flowers are usually small, and con- 

 spicuousness is gained by aggregation. The inflorescence is 

 cymose forming in the Dipsaceae and Composite dense in- 

 volucrate heads, and not infrequently contracted in the other 

 families belonging to this group into capitate clusters provided 

 with an involucre, as in Ccphaclis ipecacuana of the Kubiaceie. 

 Both actinomorphic and zygomorphic flowers occur, and the 

 sexes may be united or separated. By some writers the Rubia- 

 ceae are derived from the Umbellifene. While this derivation 

 is doubtful the terminal groups of the Choripetakc and (iamo- 

 petake certainly possess many points of resemblance, which 

 indicate a parallel development. 



The Rubiales, which include the Rubiaceae and Caprifoliaceas, 



in the first of the two families but rarely in the second. 

 Stipules occur elsewhere in the Gamopetalae only in the prim- 

 itive stem family of the Loganiaceas. The corolla varies 

 greatly in length from rotate to funnelform and tubular, and is 

 in consequence adapted to a great variety of visitors. 



The Rubiacene, or madder family, is ot immense extent in the 



