THE SYMMETRICAL CONCENTRATED TYPE. 



143 



definitely symmetrical, and thus producing a series of members 

 simultaneously instead of one by one. 



The specialisation of the construction is thus simply indicated : 

 the cumbrous method of building a radial system by the addition of 

 individual members, which initiates the mechanism of the pre- 



Fig. 55.— Symmetrical construction (5 + 5), representing the condition of true 

 pentamery as obseryed in the flowers of many Dicotyledons. 



ceding type, is swept away ab initio, and with it vanishes all the 

 preceding geometrical considerations of spiral-vortices, ideal angles, 

 and restricted attempts at symmetry. 



How small the actual change may be in a given apex, is indi- 

 cated by the close approximation of the genetic spiral to a circle, 



