''Cystopteris tenuis'' is sometimes known as Mackay's bladder fern or Mackay's fragile fern. It was long considered to be a part of the superspecies for fragile ferns, as ''Cystopteris fragilis''
( L.) Bernh.
Johann Jakob Bernhardi (1 September 1774, in Erfurt – 13 May 1850, in Erfurt) was a German doctor and botanist.
Biography
Johann J. Bernhardi studied Medicine and Botany at the University of Erfurt, and after graduation practiced medicine for a ...
var. ''mackayi''
Lawson
Lawson may refer to:
Places Australia
* Lawson, Australian Capital Territory, a suburb of Canberra
* Lawson, New South Wales, a town in the Blue Mountains
Canada
* Lawson, Saskatchewan
* Lawson Island, Nunavut
United States
* Lawson, Arkansas
...
.
left, ''C. tenuis'' in native habitat
This species is an allotetraploid of hybrid origin (see
Cystopteris hybrid complex
''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 ...
). The parent diploid species are ''
Cystopteris protrusa'' and the hypothesized ''Cystopteris hemifragilis'', believed to be an extinct species.
''C. tenuis'' is known to hybridize with ''
C. bulbifera'' to produce the hybrid ''C. Xillinoensis'', with ''
C. tennesseensis'' top produce the hybrid ''C. Xwagneri'', and with ''
C. fragilis'' and ''
C. protrusa'' to produce unnamed hybrids (as per Flora of North America).
Mackay's fragile fern grows on rock or in scree, generally in sheltered spots, in the northeastern
United States. It may be distinguished from the somewhat similar ''
Cystopteris tennesseensis'' by the fact that it grows on acid substrate, while the ''tennesseensis'' grows on calcareous substrate. The fronds of ''tenuis'' are broader, with generally alternate pinnae, while ''tennesseensis'' is narrower, with generally opposite pinnae.
tenuis
Ferns of the United States
Flora of the Great Lakes region (North America)
Flora of the Northeastern United States
Plants described in 1803
Flora without expected TNC conservation status
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