''Cystopteris protrusa'' is a common fern of North America, commonly known as the lowland bladderfern, lowland brittle fern or lowland fragile fern. The plant is native to eastern Canada, and the

Midwestern The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of the United States. I ...

and

Eastern United States The Eastern United States, commonly referred to as the American East, Eastern America, or simply the East, is the region of the United States to the east of the Mississippi River. In some cases the term may refer to a smaller area or the East C ...

. Throughout much of its range it is the most common ''

Cystopteris ''Cystopteris'' is a genus of ferns in the family Cystopteridaceae. These are known generally as bladderferns or fragile ferns. They grow in temperate areas worldwide. This is a very diverse genus and within a species individuals can look quite ...

'' fern species.

Description

Unlike most species of the genus ''

'', this fern is exclusively terrestrial, often forming large, dense colonies. It is also largely a spring ephemeral. Some fronds may remain by late summer, but most have disappeared. The specific name, protrusa, refers to the fact that the rhizome protrudes a short distance beyond the current year's fronds to form the following year's leaf buds. This protrusion is a positive diagnostic in the field. Sori are round and covered in a bladder-like indusium.

Taxonomy

''Cystopteris protrusa'' was originally considered only a variety of ''

Cystopteris fragilis ''Cystopteris fragilis'' is a species of fern known by the common names brittle bladder-fern and common fragile fern. It can be found worldwide, generally in shady, moist areas. The leaves are up to 30 or 40 centimeters long and are borne on fles ...

''. However, it is now known that this is a diploid species, while ''C. fragilis'' (ss) is a polyploid species of hybrid origin. ''C. protrusa'' is a parent of the hybrid species ''

Cystopteris tennesseensis ''Cystopteris'' is a genus of ferns in the family Cystopteridaceae. These are known generally as bladderferns or fragile ferns. They grow in temperate areas worldwide. This is a very diverse genus and within a species individuals can look quite ...

'' and '' Cystopteris tenuis''.

References

External links

USDA Plants Profile for ''Cystopteris protrusa'' (lowland bladderfern)
protrusa Ferns of Canada Ferns of the United States Plants described in 1935 {{Polypodiales-stub

Description

Taxonomy

See also

References

External links