Letter/Copy Letter

From H S M Coxeter, University of Toronto [1907-2003, mathematician], expresses an interest in Turing's Morphogenesis papers and says he is currently working on phyllotaxis. In his reply, Turing's says that he used to share Coxeter's view that the advance up the Fibonacci series is due to evolution, but now sees it differently: "According to the theory I am working on now there is a continuous advance from one pair of parastichy numbers to another, during the growth of a single plant". This may or may not relate to evolutionary development. Expects him to ask how moves from one integer to another. Turing believes "there are a number of different ways in which the parastichy numbers can be reckoned, some are more natural than others", saying different numbers come into prominence at different stages and gives example of a sunflower. Turing considers "Church is hopelessly confused about it all", but that he himself does not have "any really satisfactory account" of the matter but hopes to get one in about a year's time.