Danaea is a fern genus of approximately 50 species in the eusporangiate fern family Marattiaceae. 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 Isla del Coco (Cocos Island) in the Pacific. The genus name of Danaea is named after the Greek mythology, Danaë, an Argive princess and mother of the hero Perseus by Zeus. 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 epic Kalevala. The basal chromosome number for this genus is 2n=80. The type species is Danaea nodosa. Taxonomy Danaea is the basal lineage in the Marattiaceae and the oldest fossils are from the Paleocene, a period where rainforests became more abundant. It has radiated in these early rainforests and presently counts about 50 species in 3 sections: sect. Danaea, sect. Arthrodanaea and sect. Holodanaea. Species Danaea acuminata Tuomisto & R.C.Moran Danaea alata Sm. Danaea antillensis Christenh. Danaea atlantica Christenh., E.M.Almeida & L.P.Felix Danaea arbuscula Christenh. & Tuomisto Danaea bicolor Tuomisto & R.C.Moran Danaea bipinnata Tuomisto †Danaea borealis Pabst Danaea carillensis H.Christ Danaea cartilaginea Christenh. & Tuomisto Danaea chococola Christenh. Danaea crispa Endrés Danaea danaëpinna Christenh. Danaea draco Christenh. Danaea epiphytica Christenh. Danaea erecta Tuomisto & R.C.Moran Danaea excurrens Rosenst. Danaea falcata Tuomisto & R.C.Moran Danaea geniculata Raddi Danaea grandifolia Underw. Danaea humilis T.Moore Danaea imbricata Tuomisto & R.C.Moran Danaea × jamaicensis Underw. (D. jenmanii × D. mazeana)) Danaea jenmanii Underw. Danaea kalevala Christenh. Danaea latipinna Tuomisto & R.C.Moran Danaea leprieurii Kunze Danaea leussinkiana Christenh. Danaea lingua-cervina Christenh. & Tuomisto Danaea longicaudata Tuomisto Danaea mazeana Underw. Danaea media Liebmann Danaea moritziana C.Presl Danaea nodosa Sm. Danaea oblanceolata Stolze Danaea × plicata H.Christ (D. carillensis × D. crispa) Danaea polymorpha Lepr. ex Baker Danaea quebradensis Christenh. Danaea riparia Christenh. & Tuomisto Danaea sellowiana C.Presl Danaea simplicifolia Rudge Danaea tenera C.V.Morton Danaea trichomanoides Spruce ex T.Moore Danaea trifoliata Reichenb.