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Brittle Bladder Fern

Cystopteris fragilis

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Plant Profile

Cystopteridaceae (Bladder Fern)
Life Cycle:
Maximum Size:
40 centimetres tall
Cliffs, fields, gardens, rocky places, walls, woodland.
Ferns are flowerless and have spores instead.
Black spores with whitish cases, ripening from June to September.
Similar in appearance to a small Lady Fern (Athyrium filix-femina). The frond (leaf) tapers at the end into a point. Lady fern also tapers towards its base where it joins at the stem. The leaves are green, 2 or 3-pinnate and have tufted leaf stalks that are blackish at the base. In leaf from April to November. The fragile leaves are narrowly oblong. Grows mainly in limestone regions.
Other Names:
Aspidium Fragile, Brittle Fern, Common Fragile Fern, Fragile Fern, Green Spleenwort.
Frequency (UK):

Similar Species

Other Information


Cystopteris fragilis, also known as the fragile fern or brittle bladderfern, is a species of fern that is native to Europe, Asia, and North America. It is a small to medium-sized fern that typically grows in rocky crevices, on cliffs, and on ledges in damp, shady environments.

The fronds of C. fragilis are triangular in shape and are typically 10-40 cm long. They are deeply lobed, with the lobes being lanceolate in shape. The stipe (the stem of the frond) is typically red-brown in color, and the rachis (the axis of the frond) is typically green. The sori (clusters of spore-producing structures) are located on the undersides of the fronds, and are protected by reflexed marginal flaps.

C. fragilis is considered to be a vulnerable species in some parts of its range, due to the destruction and degradation of its habitats. However, it is not considered to be globally threatened, and is relatively common in many parts of its range.

It is a great fern for rock gardens, hanging baskets, and for use as a terrarium plant. It can also be grown in crevices of walls, rocks or stones, as well as in pockets of soil in rock gardens. It prefer to be in moist, shaded, or partially shaded areas, tolerates well cold.

It is also used traditionally in many cultures as medicine and food, because of high concentration of some essential minerals and vitamins.


The Brittle Bladder Fern, Cystopteris fragilis, is a delicate and fascinating plant that can be found in many parts of the world, including Europe, Asia, North America, and parts of South America. It is a member of the Cystopteris genus, which includes around 20 species of ferns.


The Brittle Bladder Fern is a small, herbaceous perennial that typically grows to around 20-40 cm in height. It has a thin, wiry stem that supports delicate, pale green fronds. The fronds are pinnate, with numerous small, oval-shaped leaflets that are finely toothed at the edges. The plant gets its common name from the fragile nature of its fronds, which easily break off when touched or disturbed.


Brittle Bladder Ferns are typically found in moist, shady areas, such as the edges of forests, along streams and rivers, and in damp meadows. They prefer slightly acidic soils that are rich in organic matter and tend to grow in colonies.


The Brittle Bladder Fern reproduces both sexually and asexually. It produces spores, which are released from the underside of the fronds and dispersed by the wind. These spores can develop into new plants when conditions are favorable. The plant can also reproduce asexually through its rhizomes, which can produce new shoots that grow into new plants.


Brittle Bladder Ferns have a number of traditional medicinal uses, particularly in Native American cultures. The plant was used to treat a variety of ailments, including colds, coughs, and fevers. It was also used topically as a poultice to treat cuts and wounds. The fern is still used today in some herbal remedies.


While the Brittle Bladder Fern is not currently listed as a threatened species, it is considered vulnerable in some regions due to habitat loss and degradation. Like many ferns, it is also sensitive to air pollution and changes in climate. Conservation efforts are focused on protecting and restoring the fern's habitat, as well as monitoring populations to ensure their long-term survival.

The Brittle Bladder Fern is a fascinating and beautiful plant with a long history of traditional medicinal use. While it faces some conservation challenges, its delicate fronds and ability to reproduce both sexually and asexually make it a resilient and adaptable species.

Ecological Role

The Brittle Bladder Fern provides important habitat and food for a variety of animals, including insects, snails, and small mammals. The fronds of the fern can also help to stabilize soil and prevent erosion.


Brittle Bladder Ferns are popular with gardeners and can be grown in a variety of settings, including rock gardens, woodland gardens, and container gardens. They prefer moist, well-draining soil and partial shade. The ferns can be propagated by division or by planting spores.


The Brittle Bladder Fern is a member of the Cystopteridaceae family, which includes around 10 genera of ferns. Within the Cystopteris genus, the Brittle Bladder Fern is one of the most widely distributed and well-known species.


In some cultures, the Brittle Bladder Fern is associated with healing and regeneration. Its delicate, graceful appearance is also sometimes seen as a symbol of fragility and vulnerability.

The Brittle Bladder Fern is a fascinating and important plant that is beloved by gardeners and holds traditional cultural significance. While it faces conservation challenges, efforts to protect and restore its habitat can help to ensure that it remains a part of our natural world for generations to come.

Facts about the Brittle Bladder Fern

Here are some additional interesting facts about the Brittle Bladder Fern:

  • The Brittle Bladder Fern gets its scientific name, Cystopteris fragilis, from the Greek words kystis, meaning "bladder," and pteris, meaning "fern." The species name, fragilis, means "fragile," which refers to the delicate nature of the fronds.

  • The fern's spores are housed in structures called sporangia, which are located on the undersides of the fronds. When the spores are mature, the sporangia burst open, releasing the spores into the air.

  • The Brittle Bladder Fern is one of the earliest ferns to emerge in the spring, often appearing in March or April, well before many other plants have started growing.

  • The plant is relatively short-lived, with individual fronds typically living for only a few months before dying back. However, the fern can persist for many years through its rhizomes, which can produce new fronds each season.

  • Brittle Bladder Ferns are often used as indicators of high-quality, intact habitats, as they are sensitive to disturbances such as pollution, soil compaction, and changes in hydrology.

  • The fern has a range of common names in different regions, including Fragile Bladder Fern, Brittle Fern, Brittle Bladder Fern, and Northern Bladder Fern.

In conclusion, the Brittle Bladder Fern is a fascinating plant with a range of interesting characteristics and ecological roles. Its fragility and sensitivity to environmental changes make it an important species to study and protect, both for its own sake and for the sake of the many animals that depend on it.

Distribution Map

Reproduced by kind permission of the BSBI.

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