Intraspecies or interspecies crossings transfer relevant alleles between plants. However, some interspecies crossings involving Passiflora species impede ovule fertilization and the viable development of seeds. Thus, the purpose of this study was to verify the viability of interspecific crossings and monitor pollen tube development. The experiment had six species of Passiflora in the reciprocal crossings. Histochemical tests aimed to evaluate the percentage of intraspecies or interspecies crossings that resulted in fruit development and pollen tube development. Ovule fertilization and fruit development occurred in determined directions of crossings when controlling the female or male genitor, but only one case of reciprocal crossing had success. In crossings with no fruit development, histological analysis showed that some callus developed in the stigma and style, confirming unilateral and interspecies incompatibility in the genus Passiflora to some species and some directions of crossings.