Palynotaxonomy of Iridaceae Juss. from Goiás and Tocantins States, Brazil

Abstract

The pollen morphologies of 18 native species of Iridaceae from central Brazil Goias and Tocantins States were investigated in order to understand the palynology and taxonomy of some Brazilian Iridaceae. Pollen grains were acetolyzed, measured, and studied via light microscopy and scanning electron microscopy. The measurement data was analyzed by descriptive and multivariate statistics. The pollen grains are studied for the following characteristics: monads, medium-to-large in size, bilateral symmetry; heteropolar or isopolar; amb ellipsoidal or spheroidal, biconvex, plane-convex or spheroidal in equatorial view; 1-sulcate or zonasulculate; microreticulate or reticulate, exine with smooth simplicolumellate muri, narrow or wide, straight or curved, continuous or discontinuous; rounded or polyhedral lumina, filled with or without granules; sexine thicker than nexine, tectum with similar thickness as nexine in most species. The results allowed the distinction of genera and most species, showing that pollen morphology can contribute to taxonomic studies. The observed variation in pollen morphology of the species occurring in the study region allowed us to characterize the family as eurypalynous. These data emphasize the importance of pollen morphology for identification and diagnosis of genera in Iridaceae.