MULTIJUGATE TYPES. 



175 



system, so that the point at which error crept in may be located. 

 A construction on Hnes similar to those used for Helianthus may 

 be arranged ; a still closer approximation to the observed phenomena 



Fig. 66. — Dipsacus fullonum. Section of developing capitulum showing nonnal 

 expansion (6 + 10) to (16 + 26) in agreement with the theoretical construction 

 (genetic spiral reversed). On one side of a line drawn through 5 and 5', the 3 long 

 curves expand normally to 8 ; on the other side (shaded) 5 short curves become 

 3- 2- 3- 2- 3 = 13, the two halves of the bijugate system being inverted images of 

 each other. 



M 



