This palynological study of the genus Utricularia (Lentibulariaceae) deals with 39 species spread through 26 of the 35 sections that compose the genus. The pollen varies from tricolporate to zonocolporate or to zonoporate. The tectum is smooth, rarely ornamented (SEM). Nine pollen types are distinguished of which six have been studied with the TEM. The tectum is regular, the infratectum generally granular. The foot-layer is thick if the number of apertures is reduced and thin or absent if the endoapertures form an endocingulum. The endexine is thick if the foot-layer is thin, and made up of lamellae and rarely of costae bordering the endoapertures. In the porate pollen, the foot-layer and endexine are absent. Diverse in the terrestrial and lithophytic species, the pollen tends to be oblate and planaperturate in the epiphytes, zonocolporate with numerous apertures in the floating aquatic species, and ornamented in those of flowing water. The species considered the most primitive are terrestrial with tricolporate pollen. All the other types are derived, especially those with a significant increase in the number of apertures, associated or not with the absence of a foot-layer or an endexine. In the genus Utricularia and the Lentibulariaceae in general, the variation in pollen is much less related to habitat than to the evolutionary history of each species.Key words: pollen, morphology, exine, ultrastructure, Utricularia, Lentibulariaceae.
A contribution to the knowledge of exine ultrastructure in subtribeAnisopappinae(Athroismeae, Asteraceae)