Caracteres foliares são informativos para o reconhecimento de clados em Myrteae (Myrtaceae)

Abstract

All Myrtaceae that occur in Brazil are included in Myrteae, the richest tribe. Although the phylogenetic relationships based on molecular data have shown to be stable, the morphological recognition of Myrteae clades is still incipient, especially regarding leaf characters. In this sense, this study aimed to test the hypothesis that leaf morphological characteristics are informative for the recognition of clades in Myrteae. Seven genera were selected, of which 5% of the representatives of each genus were sampled, totaling 55 species: Campomanesia (3 species), Eugenia (20), Myrceugenia (3), Myrcia (20), Myrciaria (3), Plinia (3) and Psidium (3). Sequences of seven molecular markers were obtained from GenBank. The molecular matrix was concatenated and used to infer a phylogenetic hypothesis by Maximum Likelihood. Morphological characters were obtained through the analysis of 165 images of specimens from virtual herbaria. Arrays with discrete and continuous characters were contrasted with recovered phylogenetic relationships. The results of this study show that the exmedial tertiary vein pattern is consistent with the recognition of Myrciaria. Myrceugenia and Psidium share the admedial pattern of tertiary veins. Myrcia and Eugenia share the composite intersecondary type of tertiary veins. Myrcia had the highest variability for the continuous data, except for the distance between secondary veins, a character that can be investigated by including more species. Campomanesia can be recognized by the camptodromous-brochidodromous secondary veins. Myrciaria and Myrceugenia share the secondary vein pattern, in which the collector vein looks continuous and quite close to the leaf margin. The secondary and tertiary vein patterns, in addition to the distance between the collector vein and the leaf margin, seem to be characters linked to the genera and, therefore, corroborate the hypothesis that leaf characters can be used for the recognition of Myrteae clades.