AMT C24/7

A suitable form for the lattice is the limiting divergence ratio lattice described in part I. (NB reference to part I) Clearly this description cannot hold at all times. It breaks down for the period during which the pattern is beginning to form. There may also be a period during which there is a pattern with reflexion symmetry (e.g. a decussate pattern), and the formula above will be invalid for this period also. The sections which follow are concerned with describing the chemical conditions under which this sort of description of the pattern, very broadly holds.

At a certain point in the development of the daisy the anatomical changes begin. From this point, as has been mentioned it becomes hopelessly impracticable to follow the process mathematically; nevertheless it will be as well to describe how the process does proceed (at least in the authors opinion). In the regions of high concentration of one of the morphogens growth is accelerated, and subsequently florets appear. Also the chemical pattern begins to spread inwards towards the apex, and the florets follow it. The wavelength of course remains essentially unaltered during this inward movement and therefore as the apex is approached the parastichy numbers fall, producing the usual disc pattern, possibly with some slight irregularity at the very centre. There may be still be some growth of the capitulum itself, but the pattern can no longer adjust itself to keep the wavelength constant. Either the chemical pattern has lost all its importance and gives way to