Rubiaceae is one of the richest botanical families in the Atlantic Forest, which is considered one of its main dispersion centers and where it is has high endemism. The present study aims to compare leaf anatomy and micromorphology, and to establish diagnostic characters to delimit hierarchical groupings for 17 species of different Rubiaceae taxa. For evaluation of leaf anatomy, plant material was processed following standard techniques for light and electron microscopy, including histochemical analysis. Twenty-five traits of petiole and leaf blade were identified and submitted to statistical analysis. Amaioua intermedia Aubl. differed from subfamily Rubioideae by showing short tector trichomes with their basal portion located below the level of the epidermal cells. Rudgea species differed from those of the tribe Coussareeae by presenting a continuous open arc vascular system in the median region of the petiole (except for Rudgea vellerea). Coussarea species was distinguished from Faramea due to flattened open arc system in the midrib, which was also observed in R. vellerea. Trichome type, trichome surface ornamentation, vascular system organization, type and location of mineral inclusions and sinuosity of the anticlinal wall of the epidermal cells supported species differentiation.
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