Anatomia Comparativa de Foliólulos de Mimosa (Fabaceae, Caesalpinioideae, clado Mimosoide, seção Habbasia): contribuições à taxonomia

Abstract

Mimosa is one of the largest genera in the subfamily Caesalpinioideae with around 600 species. Among the species, around 90% are found in the New World and the rest in Africa and Asia. The monophyly of the genus has been evidenced in phylogenetic analyses, however, the same does not occur for the sections, requiring additional studies. Therefore, the objective of the present work was to survey the morphoanatomical characters of the leaflets potentially useful for the taxonomy of the genus. 12 Mimosa taxa from the sect. Habbasia were analyzed, using traditional methods in plant anatomy for historesin embedding, histochemistry and clearing. Anatomical characters useful for taxonomy were: leaflet shape, apex shape, type of venation pattern, type of stomatal complex, types of trichomes, cuticle thickness, thickness of the external periclinal wall of the adaxial surface, shape of epidermal cells in cross section, evident paravenal parenchyma and cellular composition of the margin. Glandular trichomes on the margin of the leaflets have diagnostic value at the specific and infra-specific level. Some morphoanatomical characters occurred in all taxa evaluated and may be useful in consolidating this group of species from the Habbasia section.