James Small. 
138 
eously and are of similar dimensions, whereas the space for each 
floret in the geometrical system grows gradually smaller. 
The fall does not appear to take place with the same regularity 
as the rise, but the Fibonacci ratios occur and mark positions of 
relative stability in the progress of the fall. The 21 long spirals 
continue, but the 34 short spirals become approximately 13 ; these 
would become the long spirals of the (13 + 21) curve system of the 
centre. 
Fig. 24. Curve-tracing 
of the preceding : the ray 
florets are blocked in and 
the areas numbered in 
agreement with the 
theoretical construction 
of Fig. 22. (Figure and 
legend after Church.) 
In the upper half of Fig. 24 a tendency to the same 2: 1:2: 1 :2 
arrangement of the spirals as occurs in the rising phyllotaxis can 
be seen. Church gives photographs of capitula in which the falling 
phyllotaxis of the centre of the disc is more distinct, but observations 
can be made with most facility on actual fruiting heads of the 
sunflower and more than one “ falling ” transition can sometimes 
be distinguished. 
