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Asplenium scolopendrium is a common species in Europe, but in North America occurs as rare, widely scattered populations that have been given varietal status, A. scolopendrium var. americanum. Morphological differences are minor, but the North American populations are tetraploid, whereas those occurring in Europe are diploid.
In the United States, A. scolopendrium var. americanum was declared endangered in 1989. The reason that the European variety is relatively widespread, and the American variety a rarity, has apparently not been established. A third variety, A. scolopendrium var. lindenii, occurs in southern Mexico and Hispaniola.
The plants are unusual in being ferns with simple, undivided fronds. The tongue-shaped leaves have given rise to the common name "Hart's tongue fern"; a hart being an adult male red deer. The sori pattern is reminiscent of a centipede's legs, and scolopendrium is Latin for "centipede". The leaves are 10–60 cm long and 3–6 cm broad, with sori arranged in rows perpendicular to the rachis.
The plants grow on neutral and lime-rich substrates, including moist soil and damp crevices in old walls, most commonly in shaded situations but occasionally in full sun; plants in full sun are usually stunted and yellowish in colour, while those in full shade are dark green and luxuriant. The rare occurrences of the North American form in the southeastern US are found exclusively in sinkhole pits. These populations may be relics of cooler Pleistocene climates.
A. scolopendrium, with its close relative A. sagittatum, has also been placed in a segregate genus Phyllitis. A. scolopendrium forms hybrids with other Asplenium species, including those species sometimes classified in the separate genus Camptosorus, which is one reason that both Phyllitis and Camptosorus species are now generally included in Asplenium. On the other hand, a recent phylogenetic study of the Aspleniaceae family suggests that A. scolopendrium is only distantly related to other Asplenium species, and that the genus Phyllitis should again be recognized.
Asplenium scolopendrium is often grown as an ornamental plant, with several cultivars selected with varying frond form, including with frilled frond margins, forked fronds and cristate forms. This plant has gained the Royal Horticultural Society's Award of Garden Merit.
The American variety is reputed to be difficult to cultivate, and even in North America most, if not all, cultivated plants are derived from the European forms.
- "BSBI List 2007" (xls). Botanical Society of Britain and Ireland. Retrieved 2014-10-17.
- "Flora of North America: Asplenium scolopendrium var. americanum".
- Currie, Robert R. (September 1993). American hart’s-tongue recovery plan (PDF) (Report). Atlanta, Georgia: U.S. Fish and Wildlife Service. Retrieved 2010-02-28.
- "Flora Europaea: Asplenium scolopendrium".
- Short, John W.; Spaulding, Daniel D. (2012). Ferns of Alabama. Tuscaloosa, AL: University of Alabama Press. ISBN 9780817356477.
- Murakami, N.; Nogami, S.; Watanabe, M.; Iwatsuki, K. (1999). "Phylogeny of Aspleniaceae inferred from rbcL nucleotide sequences". American Fern Journal. 89: 232–243. doi:10.2307/1547233. JSTOR 1547233.
- "RHS Plant Selector - Asplenium scolopendrium". Retrieved 5 June 2013.
- Mickel, John T. (2003). Ferns for American Gardens. Timber Press. ISBN 9780881925982. This book is a reprinting of Mickel, John T. (1994). Ferns for American Gardens. MacMillan.
- Hill, John (1812). The family herbal: or An account of all those English plants, which are remarkable for their virtues, and of the drugs which are produced by vegetables of other countries; with their descriptions and their uses, as proved by experience. C. Brightly and T. Kinnersley. p. 162.
- Hyde, H. A., Wade, A. E., & Harrison, S. G. (1978). Welsh Ferns. National Museum of Wales. ISBN 0-7200-0210-9.
- Parker, Rosemarie (December 2009). "A Real Rarity". Finger Lakes Native Plant Society. A popular article on hart's tongue fern that includes several references and a discussion of cultivation possibilities for the European and American varieties. The article strongly discourages collection and or cultivation of the North American variety.
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