Palynology of Ochnaceae from the Itatiaia National Park, Brazil

Abstract

Itatiaia National Park was the first conservation unit created in Brazil and houses an important remnant of the Atlantic Forest in the Serra da Mantiqueira. The pollen morphology of six species that occur in this locality was analyzed. Pollen material was submitted to acetolysis, measured and photographed, and the data submitted to statistical treatment including multivariate analyses. In addition, pollen grains were submitted to scanning electron microscopy in order to perform a more detailed examination of sexine ornamentation. The results revealed small pollen; subprolate only in S. erecta and prolate spheroidal in the other species; 3‐colporate; sexine ornamentation varying among microreticulate‐striate, rugulate‐striate and striate. Cluster analysis revealed that Ouratea and Sauvagesia form distinct groups. Although the qualitative characters overlap, the genres Ouratea and Sauvagesia are clearly differentiated in multivariate analysis based on metric variables. This work provides, for the first time, descriptions of pollen morphology for Ouratea camposportoi. It can be concluded that the most informative pollen attribute for species delimitation was sexine ornamentation. Palynology proved to be a useful tool for delimiting species, thus aiding taxonomic studies of Ochnaceae.