Traces of ancient Dichotomies in angiosperms. (A contribution to our Knowledge of Phyllospory and Stachyospory)

It is a generally accepted concept nowadays that dichotomy is the most primitive type of ramification in land plants. Recently Lam (1948) briefly reviewed the literature of this subject in the light of the telome theory. He recalled that the dichotomies of fern leaves are to be regarded as homologous to the dichotomies of stems in more primitive plants and enumerated a number of more or less haphazardly collected cases in higher plants, of which the most probable interpretation is that they are traces of such ancient dichotomies, betraying their original relation to a branch system. In his paper, Lam discriminated between such traces in vegetative and in reproductive parts and he arrived at the provisional conclusion that traces of ancient dichotomies in the vegetative parts should particularly occur in what he termed the ‘phyllosporous’ plants, and that those of the reproductive parts are particularly found in the ‘stachysporous’ groups.