The constraints of global form on phyllotactic organization: The case of Symplocarpus (Araceae)

The present paper describes a formal analysis of the constraints imposed by a change of global form on the phyllotactic organization in the inflorescence of Symplocarpus. By combining a dynamic model of phyllotaxis with a general model of allometric growth, we show that as the length-to-width ratio of the inflorescence increases, then the number of parastichies decreases while the plastochrone ratio increases. Subsequent observations prove that these theoretical conclusions emerging from the analysis of the global form of Symplocarpus are exact. Our analysis offers experimentalists the possibility of verifying the existence of particular allometric relationships in the different phases of development of Symplocarpus and related species. (C) 1996 Academic Press Limited