Integrating Morpho-Anatomy and Histochemistry to Characterize Native Brazilian Eugenia Species

Eugenia L. (Myrtaceae Juss.) is widely distributed in Brazil and holds notable medicinal, nutritional, and economic relevance. This study expands the morpho-anatomical, micromorphological, and histochemical characterization of eight species: E. brasiliensis, E. involucrata, E. longipedunculata, E. myrcianthes, E. neoverrucosa, E. punicifolia, E. pyriformis, and E. uniflora. Morphological analyses revealed diagnostic variations in leaf blade dimensions, petiole structure, and margin traits, including the wavy margin of E. neoverrucosa. Foliar epidermal cells ranged from polygonal to sinuous, and cuticular ornamentation varied from slightly to strongly striated. Nonglandular trichomes occurred in E. myrcianthes, E. punicifolia, and E. pyriformis, with sand crystals found exclusively in E. myrcianthes. All species exhibited a uniseriate epidermis, and only E. myrcianthes showed a hypodermis. Secretory cavities were present but not uniformly distributed among organs. Stem anatomy showed brachysclereids in most species and fibers in E. involucrata and E. myrcianthes. Histochemical tests detected lipids, lignin, phenolics, and starch in all species. Various types of calcium oxalate crystals were recorded, including platy aggregate crystals reported for the first time in E. pyriformis. These integrated data provide novel structural and chemical markers relevant for species delimitation and chemotaxonomic studies within Eugenia.