Abstract—Microlicieae is a Neotropical tribe of Melastomataceae, and most of its species are endemic to Brazil, especially in campo rupestre sites. The campo rupestre ecosystem occurs in areas with shallow soils deficient in water and nutrients, and elevations above
900 m. Foliar characters provide important structural features which are of taxonomic value for Melastomataceae. Due to the high degree of endemism, taxonomic issues, and variety of water economy strategies found in Melastomataceae, our objective was to evaluate the leaf structure in 25 species
of Microlicieae, aiming to identify potentially taxonomically informative characters which may have favored the radiation and diversification of this tribe. According to our results, Lavoisiera seems to be homogeneous regarding leaf characters, while Microlicia and Trembleya
are highly variable in leaf size and general structure of veins and mesophyll. The leaf xeromorphism was presumably a relevant factor in the diversification of this tribe. Rhynchantera exhibited mesomorphic leaf characters, suggesting that the emergence of these features occurred after
the divergence of this group from the rest of the clade.
The Rubiaceae tribe Psychotrieae sensu lato and its two largest genera, Psychotria L. and Palicourea Aubl., have been considered taxonomically controversial for a long time. We aimed to identify structural features of the ontogeny of the fruits and seeds with taxonomic potential for the tribe by using species of these two genera, and Rudgea jasminoides (Cham.) Müll.Arg. The samples were obtained from a herbarium and from Brazilian state parks, and sectioned by using a rotation microtome. The fruits were found to be derived from an inferior ovary, and were characterised by a fleshy mesocarp and sclerenchymatic sinuate pyrene. The seeds were pachychalazal and arillate. The fruit was classified as a pomaceous drupoid nuculanium. The investigation showed the utility of some fruit features to discriminate species. Our study also showed that ontogenetic features of fruits and seeds are very homogeneous in Palicourea and Psychotria, which supports the inclusion of both genera in the tribe Psychotrieae.
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