Leaf epidermal and venation studies of some Bridella species (Phyllanthaceae)

Leaf anatomical characters are valuable tools for resolving taxonomic relationships among closely related plant species. The species studied here are Bridelia atroviridis, Bridelia ferruginea and Bridelia micrantha. Bridelia species have been collected within the campus of Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria. This study examines the foliar epidermal features, transverse section anatomy, and venation patterns of Briedlia species to identify the diagnostic characters of taxonomic significance. Leaf epidermal, transverse section of leaf, and venation patterns have been studied using the standard microscopic techniques, with subsequent analysis of both qualitative and quantitative characters. All species have hypostomatic leaves with anisocytic stomata, uniseriate epidermis, thick non-striated cuticle, dorsiventral mesophyll, and collateral vascular bundles indicating generic similarity. However, interspecific variations have been observed in the epidermal cell size, stomata index and density, trichome distribution, ergastic substances, midrib tissue arrangement, and venation patterns. Bridelia micrantha is distinguished by eucamptodromous venation and larger areole area, while B. ferruginea records higher stomata index values. The combined foliar anatomical characters have proved effective for species delimitation within the genus Bridelia.