How does the deposition of cell wall components structure cell shape and function during leaf ontogenesis? Although this issue has been the subject of several studies, a wide variety of standards have been reported and many knowledge gaps remain. In this study we evaluated cell wall composition in leaf tissues of Lavoisiera mucorifera Mart. & Schrank ex DC. (Melastomataceae) regarding cellulose, pectin (homogalacturonans (HGs) and rhamnogalacturonans I (RGI)) and arabinogalactan protein (AGP) distribution during ontogenesis. Leaf primordium, as well as young and mature leaves, were submitted to histochemical analysis using calcofluor white and ruthenium red, and immunocytochemical analysis using primary monoclonal antibodies (JIM5, JIM7, LM2, LM5 and LM6). Results showed that the distribution of cell wall components depends on tissue and leaf developmental stage. At the beginning of cell differentiation in the leaf primordium, two main patterns of cellulose microfibril orientation occur: perpendicular and random. This initial microfibril arrangement determines final cell shape and leaf tissue functionality in mature leaves. During leaf development, especially in epidermal and collenchyma cells, the association of HGs with low methyl-esterified groups and cellulose guarantees mechanical support. As a result, cell wall properties, such as rigidity and porosity, may also be acquired by changes in cell wall composition and are associated with morphogenetic patterns in L. mucorifera.