Coccoloba P. Browne (Polygonaceae): Taxonomic value of new leaf anatomical and micromorphological characters in Brazilian species

Coccoloba P. Browne (Polygonaceae, Eriogonoideae) is a large and complex genus with high morphological homogeneity and difficult species identification. In order to highlight informative characters for potential use in taxonomy, leaf anatomy of 11 species of Coccoloba was investigated. Leaves were studied using light and scanning electron microscopy. It confirmed that multicellular peltate glandular trichomes, unicellular or multicellular non-glandular trichomes, mucilaginous epidermis, crystal idioblasts and collateral vascular bundles are shared by all Coccoloba species here investigated. Scleromorphic features such as fibers in subepidermal layer associated with vascular system, abundance of phenols and druses in mesophyll were found too. Information about wax micromorphology, trichome types, stomatal types, presence of papillae, presence of hypodermis, type of mesophyll and arrangement of vascular bundles in petiole can be used as diagnostic characters.