486 



Church. — Note on Phyllotaxis. 



radial direction as they approach the centre that they cannot 

 possibly represent any formation of primordia at the stem- 

 apex, on which such members are well known to arise as fairly 

 isodiametric protuberances. At the same time, it will be 

 noticed that the Archimedean spirals by construction all fall 

 into the centre and stop there, so that no room is left in the 



Fig. 2. Theory of Schimper and Braun. Construction for Phyllotaxis /j- 

 0^4. = Orthostichy line = radius vector passing through i, 22, 43, &c. Members 

 along the contact parastichies differ by 8 and 13 respectively. Genetic spiral 

 winds left. Divergence-angle = ^ of 360° = 137° 8' 34". 



system for any subsequent growth and the addition of new 

 members which naturally obtains in the plant. 



Again, further consideration shows that all spirals, whatever 

 their primary nature may have been, must necessarily pass 



