Church. — The Principles of Phyllotaxis. 



237 



however small, at which such a mathematical distribution of 'growth- 

 potential ' may be considered as accufate ; and such a region is here 

 termed a ' Growth-Cmtre.' Since the interpretation of all complex phe- 

 nomena must be first attacked from the standpoint of simple postulates, 

 it now remains to consider the construction and properties of as simple 

 a centre of growth as possible. 



Thus in the simplest terms the growth may be taken as uniform 



: hi 



Fig. 40. Scheme for Uniform Growth Expansion : a circnlar meshwork of qnasi-squares. 

 Symmetrical construction from which asymmetrical homologues are obtained by the use of logarithmic 

 spirals. 



and centric: the fact that all plant growth is subject to a retardation 

 effect or may be frequently eccentric, may at present be placed wholly 

 on one side, since the simplest cases evidently underlie these. The case 

 of uniform centric growth is that of a uniformly expanding sphere; or, 



