Canga vegetation has high ecological importance in the Serra dos Carajás, southeastern Amazonia, but it coexists with the potential threat of large-scale iron ore mining. Considering Convolvulaceae, this canga environment has only 17 species, and 15 of these species had their pollen grains described in detail in this present work, aiming to contribute to the taxonomic knowledge of critically endangered plants, including Ipomoea cavalcantei. Pollen grains were examined by light and scanning electron microscopy, and the morphological parameters obtained were statistically analyzed using principal component analysis. Therefore, Aniseia cernua was described for the first time in the literature. In general, the echinae morphology were the main differentiating character among the Ipomoea species and was the basis for the proposed pollen key. The family Convolvulaceae in Carajás is eurypalynous, and the genus Ipomoea may be classified as stenopalynous. The set of morphological characters statically treated and correlated was effective for the separation of Ipomoea.