-(Anatomy and histochemistry of secretory structures from the leaf of Casearia decandra Jacq. (Salicaceae)). Extensive investigations have emphasized the therapeutic properties of Casearia species related with compounds secreted by specialized structures in the leaves. Therefore, the objective of this study was to characterize anatomical and histochemically the secretory structures present in leaves of C. decandra. Material was collected from natural populations of Mata da Biologia (Zona da Mata of Minas Gerais State, municipality of Viçosa). Leaves were fixed in FAA and subjected to usual methodology to obtain permanent slides. The sections were stained with toluidine blue pH 4 for structural characterization, with xylidine ponceau for total protein and PAS for neutral polysaccharides. The other histochemical tests were applied to transversally and longitudinally sectioned fresh samples. The secretory system of C. decandra consists of ducts and cavities dispersed on the leaf lamina and petiole and idioblasts present in the vascular tissues, cortical parenchyma of the midrib and in the palisade parenchyma. The ducts are distributed in the cortical parenchyma of the rib and continue in this same region of the petiole. In the mesophyll there are numerous cavities in the subepidermic layer or distributed in the interface between the palisade and spongy parenchyma. Lipophilic and hydrophilic substances were detected, confirming oil-resin lipids within ducts and cavities, and phenolic compounds, of the tannin type, within idioblasts and parenchyma. Alkaloids, polysaccharides and proteins were not detected as secretory products. This work reported the presence of ducts and cavities for the genus Casearia. Histochemical tests confirm the secretory product complexity, besides indicating fundamental tissues such as sites of synthesis and/or accumulation of phenolic compounds.Key words -cavity, ducts, Flacourtiaceae, idioblasts, secretory structures RESUMO -(Anatomia e histoquímica das estruturas secretoras da folha de Casearia decandra Jacq. (Salicaceae)). Extensivas investigações têm enfatizado as propriedades terapêuticas das espécies de Casearia, propriedades estas relacionadas com compostos secretados por estruturas especializadas presentes nas folhas. Portanto, objetivou-se caracterizar anatômica e histoquimicamente as estruturas secretoras presentes nas folhas de C. decandra. O material foi coletado em populações naturais da Mata da Biologia (Zona da Mata de MG -Viçosa). As folhas foram fixadas em FAA em etanol 50% e processadas conforme metodologia usual para obtenção de laminário permanente, sendo as seções coradas com azul de toluidina pH 4,0 para caracterização estrutural, com ponceau de xilidina para proteínas totais e PAS para polissacarídeos neutros. Os demais testes histoquímicos foram aplicados a amostras frescas seccionadas transversal e longitudinalmente. O sistema secretor de C. decandra é composto por ductos e cavidades dispersos pela lâmina foliar e pecíolo, e por idioblastos presentes nos te...