214 EVOLUTION OF PLANTS 



beautiful Rhododendrons and Azaleas (Fig. 52, A) are 

 familiar, as well as the various species of cranberries, 

 huckleberries, wintergreen, etc. The trailing arbutus 

 of the Atlantic States, and the manzanita and madrono 

 (Arbutus) of the Pacific coast are also characteristic 

 types. The other two orders of the Isocarpae are repre- 

 sented by the primroses (Primulinse) and the persim- 

 mons (Diosporinae). 



The great majority of the Sympetalse belong to the 

 second division, Anisocarpse. These are especially 

 abundant in the tropics, where they form the predomi- 

 nant constituents of the vegetation. The less specialized 

 types are included in the order Tubiflorse, with regular 

 tubular or funnel-shaped flowers. Here belong the morn- 

 ing-glories, the phloxes, and nightshades, all of them 

 including familiar wild or garden plants (Fig. 52, F). 



The second order of the Anisocarpse, the Labiati- 

 florse, as the name indicates, has flowers which are usu- 

 ally strongly bilabiate, i.e. are markedly zygomorphic. 

 This, together with a reduction in the number of sta- 

 mens, indicates a more specialized type than the Tubi- 

 floras. The two most important families of the temper- 

 ate regions are the figworts (Scrophulariacese) and mints 

 (Labiatse), both of which include numerous familiar wild 

 and cultivated plants (Fig. 53, A-D). In both of them 

 the stamens are reduced to two or four, and they often 

 exhibit very perfect adaptation to cross-fertilization. 

 Allied to these, and represented in the warmer parts 

 of the United States by a few examples, is the Bigno- 

 nia family, much more abundant, however, in tropical 

 regions. Catalpa and Tecoma (the trumpet-creeper) 

 are the genera occurring within our limits. 



