Flatfork Fern
CRCritically Endangered

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

01Classification

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.

02Description

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

IUCN StatusCritically Endangered (CR)
GroupPlants
03Habitat

Habitat & Distribution

TERRESTRIALMajor
04Threats

Threats

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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

HighOngoing

Extremely limited geographic range

HighOngoing

Habitat loss from urban development

HighOngoing

Small population size and fragmentation

HighOngoing

Climate change impacts on specialized habitat

MediumOngoing
Community

Community Sightings

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07Sources

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

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