Endangered Species
Midwest Region



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American Hart's-Tongue Fern
(Asplenium scolpendrium var. americanum)


Fact Sheet

pdf version


American hart's tongue fern photo.

This fern can be found in climates as different as Canada and Alabama, suggesting that it had spread widely since the last ice age.


Status: Threatened


Habitat: This fern is found in close association with outcrops of dolomitic limestone, in coulees, gorges and in cool limestone sinkholes in mature hardwood forests. It requires high humidity and deep shade provided by mature forest canopies or overhanging rock cliffs. It prefers soils high in magnesium.


Why It's Threatened: Although this plant is found over a very wide area, from Alabama to Canada, its populations tend to be very small and isolated due to its unique habitat. Because of its natural rarity, it is particularly vulnerable to disturbance. Many activities threaten the American hart's-tongue. Quarrying, recreation and residential development have all destroyed these plants and their habitat. Canadian populations are threatened by lumbering and the development of land for ski resorts and country estates, among other activities. By removing shade trees, logging raises light levels and lowers humidity, decimating any American hart's-tongue ferns in that area.


Midwest Endangered Species


Last updated: October 15, 2015