Shoot Branching

This chapter concerns how and where shoot branches arise in the plant body. It also concerns the pattern of growth and developmental fate of branches once they grow out. Axillary branching in seed plants is thus a type of lateral branching where leaf and branch initiation are associated in time and space. Like other forms of acrogenous branching, axillary meristems are also initiated at the shoot apex but, depending upon their rate of development relative to that of the parent shoot, can exhibit varying degrees of development in the immediate vicinity of the shoot apex. The particular interest in dichotomous branching in plant morphology is because some of the oldest fossil vascular plants seem to exhibit a predominance of dichotomous branching of their axes. Hence dichotomy has been assumed to be the most primitive form of branching, and any vascular plants exhibiting dichotomy have been assumed to be evolutionarily primitive.