Flatfork Fern
Psilotum complanatum
Psilotum complanatum, the flatfork fern, is a rare herbaceous epiphytic fern ally in the genus Psilotum. There is some evidence that it might be a true fern that has lost some typically fern-like characteristics.
Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Psilotum_complanatum
Taxonomy & Classification
Kingdom
Plantae
Phylum
Tracheophyta
Class
Polypodiopsida
Order
Psilotales
Family
Psilotaceae
Genus
Psilotum
Flatfork Fern belongs to the family Psilotaceae, order Psilotales, within the Polypodiopsida class.
Species Profile
Psilotum complanatum, the flatfork fern, is a rare herbaceous epiphytic fern ally in the genus Psilotum. There is some evidence that it might be a true fern that has lost some typically fern-like characteristics. Morphologically, the plant is simple, lacking leaves and roots, and having hanging stems with dichotomous branching, which lack developed leaves but have minute scales. The stems and branches have protostele, with a triangular-shaped core of xylem. The scales are arranged in two rows along the flat stems and branches. The stems are broadly triangular in cross section and 5 mm wide. The branches are 1.5 to 2 mm wide. P. complanatum grows 10 to 75 cm long and stems branch in pairs a number of times up their length and are covered with brownish colored hair-like rhizoids. Small...
The Flatfork Fern faces severe population decline primarily due to habitat destruction from urban development and agricultural expansion in its limited range. The species' extremely restricted distribution makes it particularly vulnerable to localized threats, while its specialized habitat requirements limit opportunities for natural recolonization.
Key Facts
Habitat & Distribution
Threats
IUCN Red List: Critically Endangered
The Flatfork Fern faces severe population decline primarily due to habitat destruction from urban development and agricultural expansion in its limited range. The species' extremely restricted distribution makes it particularly vulnerable to localized threats, while its specialized habitat requirements limit opportunities for natural recolonization.
Agricultural land conversion
Extremely limited geographic range
Habitat loss from urban development
Small population size and fragmentation
Climate change impacts on specialized habitat
Community Sightings
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Sources & Attribution
How to Cite
IUCN: IUCN (2025). The IUCN Red List of Threatened Species. Version 2025-1. Available at: https://www.iucnredlist.org. doi:10.2305/IUCN.UK.2025-1.RLTS
GBIF: GBIF.org (2025). GBIF Home Page. Available at: https://www.gbif.org
This page: SpeciesRadar (2025). Flatfork Fern (Psilotum complanatum). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/flatfork-fern