taxonomic significance of pollen morphology in Tovomita Aubl. (Clusiaceae: Clusieae) and related genera

Tovomita (Clusiaceae, tribe Clusieae) comprises about 45 species with Neotropical distribution. Thirty of these species occur in the Brazilian Amazon and Atlantic forest, but have only been poorly sampled in studies of pollen morphology. Pollen grains of ten species of Tovomita and one of Tovomitopsis are characterized and illustrated here and morphologically compared with those from other extant genera of Clusiaceae s.s., as well as the fossil genus Paleoclusia (which shares with Tovomita prolate triaperturate pollen grains with reticulate exines and sexine elements inside the lumina). The pollen grains of the analyzed species of Tovomita were found to be tricolporate, with amb circular to subtriangular, and exine psilate to microreticulate. Tovomita pollen differs markedly from Tovomitopsis in terms of the tectum surface, which is smooth with regular baculate in the former, versus irregular and not smooth, with some twisted baculate processes, in the latter. Other pollen features among species of Clusiaceae are discussed in order to better characterize Tovomita and help elucidate generic limits among related genera.