The palynological diversity of Blechnaceae in the Atlantic Forest was investigated. While the monophyletic family belongs to the group of leptosporangiate ferns, a new classification proposed by recent phylogenetic study reorganizes the family and adds new genera. To expand palynological knowledge of the group, the spore morphology of 23 species and a hybrid, distributed among 10 genera, was described. Material from herbarium collections were submitted to acetolysis and mounted on slides, with subsequent statistical analysis of spore measurements. Photomicrographs of the material were taken under both light and scanning electron microscopy. Perine ornamentation varied among psilate, rugulate and scabrate; granules and gemmae were present along with thin, smooth cristae. Species of Blechnum and Austroblechnum exhibited the greatest diversity. The attributes of the spores obtained here were able to differentiate the analyzed species, although the spore morphology of some taxa was found to be very similar. Multivariate analysis assessed the relevance of quantitative data for differentiating the taxa.

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