Adiantum (), the maidenhair fern (not to be confused with the similar-looking maidenhair spleenwort fern), is a genus of about 250 species of ferns in the subfamily Vittarioideae of the family Pteridaceae, though some researchers place it in its own family, Adiantaceae. The genus name comes from Greek, meaning "unwetted", referring to the fronds´ ability to shed water without becoming wet.

 They are distinctive in appearance, with dark, often black stipes and rachises, and bright green, often delicately cut leaf tissue. The sori are borne submarginally, and are covered by reflexed flaps of leaf tissue which resemble indusia. Dimorphism between sterile and fertile fronds is generally subtle.

They generally prefer humus-rich, moist, well-drained sites, ranging from bottomland soils to vertical rock walls. Many species are especially known for growing on rock walls around waterfalls and water seepage areas.

The highest species diversity is in the Andes. Fairly high diversity also occurs in eastern Asia, with nearly 40 species in China.

Species native to North America include A. pedatum (five-fingered fern) and the closely related A. aleuticum, which are distinctive in having a bifurcating frond that radiates pinnae on one side only. The cosmopolitan A. capillus-veneris (Venus-hair fern) has a native distribution that extends into the eastern continent. A. jordanii (California Maidenhair) is native to the west coast.

There is a rich Adiantum flora in New Zealand with 3 endemic species (A. cunninghamii, A. viridescens and A. fulvum) in a total of 10 recorded species. Many of these are common especially in the west and south of the islands.

Cladistics: 

Phylogeny of Adiantum

1=Read more Source: Wikipedia, article Adiantum sp.. Content adapted from Wikipedia, available under the CC BY-SA 4.0 license. Accessed on 18/07/2026. Geographic distribution Native Exotic Loading map... ✖ • 1 record - • 2 or 3 records - • 4 to 10 records - • 11 to 50 records - • Over 51 records Species photographs Last published photographs Photography ID: 603611   Adult Parque Nacional Calilegua Jujuy Argentina 04/06/2018 Maria Belén Dri Photography ID: 525672   Adult Parque Provincial Cumbres Calchaquíes Tucumán Argentina 05/09/2019 Maria Belén Dri  View all photographs of the species  Add a photography for this sheet Species vocalizations Last vocalizations published  Add an audio for this sheet Species videos Last filmings published  Add a film for this sheet Species reports  Detail of places sorted by number of records Page 1 Record ID Date Exact time Country Province / department Place Filmed Photographed Recorded vocal Observed Heard Wounded or dead Number of individuals User or Bibliography Detail 1728042 09/05/2019 Argentina Tucumán Acceso los Cardones, Parque Provincial Cumbres Calchaquíes Maria Belén Dri 2163439 06/04/2018 Argentina Jujuy Parque Nacional Calilegua Maria Belén Dri Page 1  Add a record for this sheet 📖 Recommended citation Please use the following reference when citing this species account. EcoRegistros. 2026. Adiantum sp. – Species account. Accessed from www.ecoregistros.org on 29/09/2026.