Morfologia polínica de espécies epífitas de Cactaceae Juss. do Rio Grande do Sul, Brasil

In this paper, we studied the pollen morphology of 11 species of epiphytic Cactaceae family in Rio Grande do Sul, southern Brazil. We provide descriptions, measurements, photomicrographs, as well as information on ecology and biogeography. The pollen grains are variable in size (medium, large and giant) with prolate-spheroidal to prolate forms; 3-colpate aperture ( Lepismium cruciforme (Vell.) Miq. and Rhipsalis cereuscula Haw.) and 6-colpate (remaining species); exine with tectum and small granulate texture and perforations; except for Epiphyllum phyllanthus (L.) Haw, colpi are covered by thin granulate membrane; heteromorphism in the apertures of L. houlletianum (Lem.) Barthlott, L. warmingianum (K. Schum.) Barthlott and Rhipsalis campos-portoana Loefgr was observed. Results indicate two morphological patterns in the study taxa: the fi rst (I) is related to pollen grains with 3-colpate aperture and second (II) with 6-colpate aperture