248 SYSTEMATIC BOTANY 



and are dispersed by the wind (see Fig. 148, p. 214). In 

 the Wood Sanicle (Sanicula europaea) the fruits are hooked 

 and dispersed by animals. 



The Archichlamydeae includes upwards of sixty thousand 

 species. The more primitive forms are distinguished from 

 the higher ones by the parts of the flower being indefinite 

 in number and spirally arranged on the axis. The corolla, 

 when present, is usually polypetalous, and the ovules have 

 two coats. In Ranunculaceae the flower is hypogynous, 

 and the perianth in some species is spiral : in others, 

 cyclic. The stamens and carpels are in general spirally 

 arranged and indefinite. In Cruciferae all the whorls are 

 cyclic. In Rosaceae and Papilionaceae the flowers are 

 perigynous, and in the latter order they are irregular. In 

 the Umbelliferae many small irregular epigynous flowers 

 are massed together in conspicuous umbels. The division 

 is very complex, and the characters, even within a single 

 order, may be very variable. 



CHAPTER XX 



DICOTYLEDONS 



B. Metachlamydeae or Sympetalae 



In this division the perianth is in two whorls, and the 

 petals are united (gamopetalous). 



Order Primulaceae. Flowers often on scapes, usually 

 regular. Sepals five. Petals five, united. Stamens 

 five, epipetalous and opposite the petals. Ovary 



