Adiantum (Pteridaceae) in Brazil: Key to the species and illustrations

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.

Pteridaceae in remnants of Cerrado in Maranhão state, Brazil

“…We revised specimens at CCAA and SP and identified our new collections using the literature for the group, such as Tryon and Stolze (1989), Lellinger (1991), Moran (1995a, 1995b) Prado (2005b, 2005c, Maciel and Pietrobom (2010), Winter et al (2011), Kessler et al (2017, Prado et al (2017), andHirai (2020), as well as Neotropical floras (Smith and Lellinger 1995;Mickel and Smith 2004). The generic circumscription of the family follows PPG I (2016), the nomenclature follows the International Plant Names Index (IPNI 2022) and TROPICOS (2022), and morphological terms are based on Lellinger (2002).…”

“…Of these species, 15 occur in the Amazon domain and 21 in areas of Cerrado (Fernandes et al 2007(Fernandes et al , 2010(Fernandes et al , 2022Conceição and Rodrigues 2010;Conceição et al 2015;Silva et al 2017;Prado et al 2020). This is almost half of the total number of 50 species recorded for the family in the Brazilian Cerrado domain (Prado et al 2020).…”

“…Other notable works are Winter et al (2011) and Miranda et al (2015), who studied Adiantum L. The greatest diversity of Pteridaceae has been recorded in the Atlantic Forest of Brazil, which is a center of endemism for ferns in South America (Tryon 1972;). In the Cerrado domain, 50 species of Pteridaceae have been recorded by Prado et al (2020).…”

“…Maranhão state is in at the transition zone between three phytogeographic domains, the Amazon, the Cerrado, and the Caatinga, and this favors greater taxonomic diversity (IBGE 2004;Muniz 2006;Stella 2011), but for Pteridaceae, only 10 genera, 33 species, and three varieties have been recorded (Prado et al 2020;Fernandes et al 2022). Of these species, 15 occur in the Amazon domain and 21 in areas of Cerrado (Fernandes et al 2007(Fernandes et al , 2010(Fernandes et al , 2022Conceição and Rodrigues 2010;Conceição et al 2015;Silva et al 2017;Prado et al 2020). This is almost half of the total number of 50 species recorded for the family in the Brazilian Cerrado domain (Prado et al 2020).…”

“…It comprises 53 genera and 1,211 species (PPG I 2016), which is approximately 10% of the class. In Brazil, the diversity of Pteridaceae is estimated to be 24 genera and 207 species, of which 71 are endemic (Prado et al 2020). This diversity is directly related to the fact that the life forms in this family (aquatic, epiphytic, rupicolous, terrestrial) are the most varied among ferns, the representatives of the family have adapted to a wide range of habitats (aquatic to xeric), and these adaptations differ from those found in other fern families (Schuettpelz et al 2007).…”