Abstract : The evolution of structural parameters of the metamer, i.e. leaf area and internode volume, was analyzed during plant growth for 11 tropical species, whether trees or bushes. It is shown that transition to sexuality is related to a predominance of the foliar part of the metamer over the axial part. This gived rise to "foliarized axes". On the contrary, axes developed during the vegetative growth of the plant showed a predominance of the axial part over the foliar part. They are designated "axialized axes". Beyond its descriptive interest this work gives conceptual and quantitative tools to quantify some traits related to onotogenesis, especially flowering.