Comparative leaf anatomy and morphology of some neotropical Rondeletia (Rubiaceae) species

A comparative anatomical and morphological study on the petioles and leaves of 10 neotropical Rondeletia species (representing 10 sections) has been made in order to investigate interspecific variations which may be useful in species identification. All species have bifacial and hypostomatic leaves, contain tannins and crystal sand. The central vascular bundle in the petiole and the midrib are open to the upper side and are collateral. The species differ in presence or absence of non-glandular trichomes, in the structure of the petiole and leaf blade. A combination of these characters may be useful in species identification. The results, however, do not support the classification into 10 sections but provide a comprehensive petiole and leaf anatomical and morphological character-set typical for the genus.