Evolution of inflorescences and ornithophily in the Pimenta group (Myrteae, Myrtaceae)

Ornithophily has evolved several times among flowering plants, characterized by a passive transferring of pollen and by offering a reward primarily in the form of nectar. The use of floral structures as a reward to attract birds is less common among flowering plants. In South America there are several examples of this phenomenon among these three well documented examples of plants that have developed fleshy and sweet petals, to attract frugivorous birds. Two of these cases are found in myrtle species placed in the informal group “Pimenta” (tribe Myrteae,Myrtaceae): Acca and Myrrhinium. The phylogenetic placement of Myrrhinium has never been tested. However, because the development of floral structures as a pollination reward is so infrequent, the most plausible hypothesis is to consider the presence of fleshy petals a homology. However, other traits such as size and color of the petals as well as the architecture of the inflorescences differ between the species. In this framework, our aims are to obtain a phylogenetic position of Myrrhinium to test the homology of freshly petals in Pimenta and to analyze the evolution of the inflorescence architecture in a phylogenetic context. The study is based on nuclear (ITS) and chloroplast (rbcL, ndhF, matK, psbA-trnH) sequences amplified from own material or obtained from GenBank. Maximun Parsimony (MP) analyses were conducted using TNT software and Bayesian Inference (BI) using MrBayes software. The morphological studies were based on fresh material and herbarium material deposited at SI, as well as information obtained from the literature. Fil: Nadra, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Giannini, Norberto Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina