Ferns and lycophytes from the Cerro do Tigre and Cerro Palomas, Pampa biogeographic province, Rio Grande do Sul State, Brazil

ABSTRACT

The Pampa represents one of the domains of highest floristic richness in South America, however, especially in relation to the ferns and lycophytes, it still poorly known. This study aims to list the ferns and lycophytes associated with the Tigre and Palomas hills and discuss the floristic aspects that shape the fern and lycophyte flora at the isolated formations (Cerros) of the Pampa domain. The samples were collected and herborized using standard techniques and identified through specific literature. Herbarium specimens were also analyzed in order to complement the floristic list. Species were classified according to their geographical distribution pattern and also considering their life and growth forms. The inventory resulted in 36 species, representing four lycophytes and 32 ferns, distributed in 11 families and 19 genera. Overall, 18 species were exclusive to Cerro do Tigre, five to Cerro Palomas and 13 shared between both areas. Most of the species are widely distributed in South America (41,02%) and Tropical America (35,89%), and no endemic species to the pampean domain were identified. The predominant life form was hemicryptophyte, and rosulate was the most represented growth form. In general, the species occurring in the areas presented adaptations to xerophytic conditions. The results showed a high species richness in the studied areas in relation to cited for the whole domain, indicating that the Cerros serve as refuges for the maintenance of ferns and lycophytes in the Pampa region.

Keywords:
inselbergs; Pampa domain; pteridophytes; survey