Abstract Studies concerning the cytogenetics of Gleicheniaceae have been scarce, especially those employing evolutionary approaches. Two chromosome number evolutionary models have been hypothesized for Gleicheniaceae. One proposes that ancestral haploid numbers were small and that the chromosome numbers of extant species evolved through polyploidy. The other model proposes that, at the genus level, fern chromosome evolution occurred from ancestors with essentially the same high chromosome numbers seen in living lineages. Neither of those hypotheses has been tested based on phylogenetic frameworks. We sought to (i) present the state of the art of Gleicheniaceae chromosome numbers; (ii) test the two evolutionary models of chromosome numbers within a phylogenetic framework; (iii) test correlations between DNA contents and chromosome numbers in the family. We report here DNA C-values for five species, which increases the number of investigated taxa nearly twofold and report two new genera records. Ancestral state chromosome reconstruction corroborates the hypothesis that ancestral chromosome numbers in Gleicheniaceae were as high as those of extant lineages. Our results demonstrate the possible role of dysploidy in the evolutionary chromosome history of Gleicheniaceae at the genus level and suggest that the relationship between chromosome number and DNA content does not appear to be linear.

Resumo Este estudo trata os táxons das famílias Athyriaceae, Lomariopsidaceae, Metaxyaceae e Saccolomataceae (Polypodiopsida) encontrados nas formações de Floresta Ombrófila Densa circunvizinhas às formações de canga da Serra dos Carajás, estado do Pará, e conta com descrições, imagens, distribuição e comentários. Na área de estudo foram registradas oito espécies distribuídas em cinco gêneros.

Abstract This study addresses the families Athyriaceae, Lomariopsidaceae, Metaxyaceae and Saccolomataceae (Polypodiopsida) recorded in the rainforest surrounding “canga” formations of the Serra dos Carajás, Pará state, with descriptions, images, geographical distribution and comments. In the study area were recorded eight species distributed in five genera.

Resumo Este estudo trata os táxons da família Gleicheniaceae encontradas nas formações ferríferas da Serra dos Carajás, estado do Pará, com descrições, imagens, distribuição e comentários. Na área de estudo foram registradas duas espécies distribuídas em dois gêneros: Dicranopteris flexuosa e Gleichenella pectinata.

Abstract This study addresses the Gleicheniaceae taxa recorded in ferruginous formations of Serra dos Carajás, Pará state, with descriptions, images, geographical distribution, and comments. In the study area were recorded two species distributed in two genera: Dicranopteris flexuosa and Gleichenella pectinata.

Resumo Este estudo trata os táxons da família Marattiaceae encontrados nas formações ferríferas da Serra dos Carajás, estado do Pará, com descrições, imagens, distribuição e comentários. Na área de estudo foram registrados um gênero e duas espécies: Danaea cartilaginea e Danaea leprieurii. As duas espécies constituem registros novos para o estado do Pará.

Abstract This study addresses the Marattiaceae taxa recorded in ferruginous formations of Serra dos Carajás, Pará state, with descriptions, images, geographical distribution, and comments. In the study area one genus and two species were recorded: Danaea cartilaginea and Danaea leprieurii. The two species are new records to Pará state.