Published online by Cambridge University Press: 05 December 2011
Evolution of new forms of organisms must be accompanied by evolution of the informational processes which regulate the development of these new forms. During plant phylogeny, products of metabolism have become phytohormones through the evolution of receptor molecules. Although nothing is known about these receptor molecules, it is suggested that the schizaeaceous ferns are the most primitive group in which a gibberellin-like substance acts as a signal for morphogenesis, and that their antheridiogen pheromones, which stimulate antheridium formation and spore germination, are the ancestors of the gibberellin hormones which influence seed plant development. Chemical and biological evidence for this suggestion is discussed.