Danaea

Danaea is a genus of approximately 80 species in the eusporangiate fern family Marattiaceae.^[1] They are small to intermediately large ferns with erect or creeping rhizomes and usually once-pinnate leaves with opposite pinnae. The fertile leaves are contracted, acrostichoid and covered below with sunken, linear synangia. The genus Danaea has a neotropical distribution, occurring from southern Mexico through Central America, the Caribbean and northern South America to Bolivia, Paraguay and the Mata Atlantica in Brazil and Northern Argentina. There is also a population on Cocos Island in the Pacific.^[2][3]

The genus name of Danaea is named after the Greek mythology, Danaë, an Argive princess and mother of the hero Perseus by Zeus.^[4]

Two species Danaea carillensis (Costa Rica) and D. simplicifolia (Guianas, Brazil, Trinidad) have simple, undivided leaves, and some other species sometimes have bipinnate leaves (D. atlantica, D. bipinnata, D. nodosa, D. urbanii). One species Danaea kalevala of the Lesser Antilles was named in honour of the Finnish heroic epicKalevala.

The basal chromosome number for this genus is 2n=80. The type species is Danaea nodosa.^[1][5]

The Smith et al. classification of 2006, based on molecular phylogeny, placed Danaea in Marattiaceae.^[6] Subsequent classifications have maintained this placement.^[7][8][9]

Danaea is the earliest diverging lineage in the Marattiaceae.^[5] It has radiated in the American tropics and presently counts about 80 species in 3 subgenera: subg. Danaea, subg. Arthrodanaea and subg. Holodanaea.^[1][10]