New Highlights on the Morphoanatomy and Histochemistry of <i>Chionanthus filiformis</i> : A Native Brazilian Species

Chionanthus filiformis (Vell.) P.S. Green (Oleaceae) is an endemic species of the Atlantic Rainforest. This study provides a comprehensive morphoanatomical description of its leaves and stems, integrating light microscopy, field emission scanning electron microscopy, histochemical, and phytochemical tests. To the best of our knowledge, this is the first report on the stem anatomy and histochemistry of the species. Morphologically, the leaves are simple, opposite, dark green on the adaxial surface, and pale green on the abaxial surface. Key anatomy diagnostic characteristics comprise straight to wavy anticlinal cell walls on the adaxial epidermis, stomatal dimensions (22.99 ± 2.09 µm × 20.10 ± 1.79 µm), a stomatal index of 14.835% ± 1.75, dorsiventral mesophyll, and vascular system organization in the midrib and petiole. The morphotypes and the distribution of crystals were essentially relevant for species identification. Histochemical analysis confirmed the presence of lipophilic and phenolic compounds, neutral polysaccharides, and starch grains. Phytochemical screening detected anthraquinones, coumarins, flavonoids, steroids, and tannins, whereas two-dimensional chromatography further identified specific subgroups of coumarins, flavonoids, and triterpenoids. These findings provide novel insights into the anatomy and chemical composition of C. filiformis, contributing to its taxonomic characterization and increasing the knowledge of Chionanthus genus.