Bladderfern
Cystopteris sudetica
Bladderfern (Cystopteris sudetica) is a delicate perennial fern characterized by its finely divided, lace-like fronds that emerge from rocky crevices and cliff faces. This small to medium-sized fern typically reaches 10-30 cm in height and displays distinctive bladder-like indusia covering its sori on the undersides of fertile fronds.
Photo: iNaturalist: (c) Dmitriy Bochkov, some rights reserved (CC BY), uploaded by Dmitriy Bochkov
Taxonomy & Classification
Kingdom
Plantae
Phylum
Tracheophyta
Class
Polypodiopsida
Order
Polypodiales
Family
Cystopteridaceae
Genus
Cystopteris
Bladderfern belongs to the family Cystopteridaceae, order Polypodiales, within the Polypodiopsida class.
Species Profile
Bladderfern (Cystopteris sudetica) is a delicate perennial fern characterized by its finely divided, lace-like fronds that emerge from rocky crevices and cliff faces. This small to medium-sized fern typically reaches 10-30 cm in height and displays distinctive bladder-like indusia covering its sori on the undersides of fertile fronds. As a pioneer species in rocky environments, it plays an important role in soil formation and provides microhabitat for small invertebrates in harsh montane ecosystems.
Cystopteris sudetica faces severe population declines primarily due to habitat destruction and fragmentation of its specialized montane environments. Climate change poses an additional threat by altering the cool, moist conditions this alpine fern requires, while human activities continue to degrade its limited remaining habitat.
Key Facts
Habitat & Distribution
Bladderfern inhabits cool, moist rock crevices, cliff faces, and rocky outcrops in mountainous regions, typically at elevations between 800-2000 meters. The species shows a strong preference for calcareous substrates and north-facing slopes where it can access consistent moisture while remaining protected from direct sunlight and extreme temperature fluctuations.
Threats
IUCN Red List: Endangered
Cystopteris sudetica faces severe population declines primarily due to habitat destruction and fragmentation of its specialized montane environments. Climate change poses an additional threat by altering the cool, moist conditions this alpine fern requires, while human activities continue to degrade its limited remaining habitat.
Climate change and warming temperatures
Habitat loss and fragmentation
Changes in hydrology
Human disturbance and trampling
Small population size and genetic isolation
National vs Global Threat Status
How this species is assessed at the national level compared to its IUCN global status (EN).
| Country | National Status | Global Status | Comparison |
|---|---|---|---|
| EU | NTNear Threatened | ENEndangered | Lower local risk |
| EU | NTNear Threatened | ENEndangered | Lower local risk |
National Red List data sourced from the National Red List Project (nationalredlist.org, ZSL) and country-specific Red List authorities.
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
National Red Lists: ZSL (2025). National Red List. Zoological Society of London. Available at: https://www.nationalredlist.org
This page: SpeciesRadar (2025). Bladderfern (Cystopteris sudetica). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/bladderfern