''Asplenium ruta-muraria'' is a species of

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...

commonly known as wall-rue (but which, as a fern, is not by any means closely related to common

rue ''Ruta graveolens'', commonly known as rue, common rue or herb-of-grace, is a species of ''Ruta'' grown as an ornamental plant and herb. It is native to the Balkan Peninsula. It is grown throughout the world in gardens, especially for its bluis ...

). It is a very small epipetric species, growing exclusively on

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

and other calcareous rocks. Its fronds are bluish-green and are heavily sub-divided, becoming up to 12 cm in length.

Taxonomy

Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

first gave wall-rue the

binomial Binomial may refer to: In mathematics *Binomial (polynomial), a polynomial with two terms * Binomial coefficient, numbers appearing in the expansions of powers of binomials *Binomial QMF, a perfect-reconstruction orthogonal wavelet decomposition ...

''Asplenium ruta-muraria'' in his '' Species Plantarum'' of 1753. A global

phylogeny A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spe ...

of ''Asplenium'' published in 2020 divided the genus into eleven clades, which were given informal names pending further taxonomic study. ''A. ruta-muraria'' belongs to the "''Pleurosorus'' subclade" of the "''Pleurosorus'' clade". The ''Pleurosorus'' clade has a worldwide distribution; members are generally small and occur on hillsides, often sheltering among rocks in exposed habitats. ''A. ruta-muraria'' is exceptional within the subclade for its lack of hairs on the leaf. The phylogeny suggests that multiple

cryptic species In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

may be present among plants now called ''A. ruta-muraria''. Within the subclade, the ''A. ruta-muraria'' aggregate (including ''A. dolomiticum'') is

sister A sister is a woman or a girl who shares one or more parents with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a family, familial relationship, it is sometimes used endearingly to r ...

to the species formerly segregated in the genus ''Pleurosorus''.

Distribution and habitat

''Asplenium ruta-muraria'' is native to Europe, East Asia, and eastern North America. In North America, its range extends from western New England southwest along the

Appalachian Mountains The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They ...

to Alabama and Tennessee. It is also found in the

Ozarks The Ozarks, also known as the Ozark Mountains, Ozark Highlands or Ozark Plateau, is a physiographic region in the U.S. states of Missouri, Arkansas, Oklahoma and the extreme southeastern corner of Kansas. The Ozarks cover a significant port ...

and in southern Indiana and Ohio, with outlying occurrences in Michigan, Ontario, Quebec, and Clinton County, Iowa. In

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

, it commonly invades masonry and is a common species, while in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

, it is more difficult to find, favouring pockets in very well-weathered and rather dry limestone outcrops.

Citations

References

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External links

* * {{Taxonbar, from=Q1125768 ruta-muraria Flora of England Flora of Lebanon Ferns of the United States Flora of Connecticut Ferns of Europe Plants described in 1753 Taxa named by Carl Linnaeus