RESUMO
Abstract: Adiantum is a Pantropical genus of ferns, monophyletic, and has about 225 species. It can be recognized by the indusia with veins, bearing sporangia directly on the underside of its reflexed tissue. About 110 species occur in the Neotropical region and 65 of them are reported to Brazil. Among them, 64 are native species and occur mainly in the Amazon Rainforest, Caatinga, Central Brazilian Savanna, and in the Brazilian Atlantic Rainforest. Among the species that occur in Brazil, 16 are endemic and they represent 25% of the total. This paper presents a key to identify the 63 native species of Adiantum in Brazil, excluding the hybrid one. Illustrations of some morphological features, as well as of all species are also presented to help in the process of identification.
Resumo: Adiantum é um gênero Pantropical de samambaias, monofilético e com cerca de 225 espécies. Pode ser reconhecido pelos indúsios com nervuras e esporângios formados diretamente sobre a face inferior do seu tecido reflexo. Aproximadamente 110 espécies ocorrem na região Neotropical e 65 delas são registradas para o Brasil. Entre elas, 64 são espécies nativas e ocorrem principalmente na Floresta Amazônica, Caatinga, nas vegetações abertas do Brasil Central e na Floresta Atlântica Brasileira. Entre a espécies que ocorrem no Brasil, 16 são endêmicas e elas representam 25% do total. Este trabalho apresenta uma chave para identificação das 63 espécies nativas de Adiantum no Brasil, excluindo o híbrido. Também são apresentadas ilustrações de alguns caracteres morfológicos, bem como de todas as espécies para ajudar no processo de identificação.
RESUMO
We examined the global historical biogeography of grammitid ferns (Polypodiaceae) within a phylogenetic context. We inferred phylogenetic relationships of 190 species representing 31 of the 33 currently recognized genera of grammitid ferns by analyzing DNA sequence variation of five plastid DNA regions. We estimated the ages of cladogenetic events on an inferred phylogeny using secondary fossil calibration points. Historical biogeographical patterns were inferred via ancestral area reconstruction. Our results supported four large-scale phylogenetic and biogeographic patterns: (1) a monophyletic grammitid clade that arose among Neotropical polypod ancestors about 31.4 Ma; (2) a paraphyletic assemblage of clades distributed in the Neotropics and the Afro-Malagasy region; (3) a large clade distributed throughout the Asia-Malesia-Pacific region that originated about 23.4 Ma; and, (4) an Australian or New Zealand origin of the circumaustral genus Notogrammitis. Most genera were supported as monophyletic except for Grammitis, Oreogrammitis, Radiogrammitis, and Zygophlebia. Grammitid ferns are a well-supported monophyletic group with two biogeographically distinct lineages: a primarily Neotropical grade exhibiting several independent successful colonizations to the Afro-Malagasy region and a primarily Paleotropical clade exhibiting multiple independent dispersals to remote Pacific islands and temperate, austral regions.