Species At Risk

Hart’s-tongue Fern

(Asplenium scolopendrium americanum)

Special Concern

Hart’s-tongue Fern
Hart’s-tongue Fern occurrences map


The Hart’s-tongue Fern is a perennial evergreen fern with fronds that grow from a short and stout underground stem. Its blades are strap-shaped with a heart-shaped base and pointed tip, about 12 to 40 centimetres long or longer, and two to 4.5 centimetres wide.

Action we are taking:


Hart’s-tongue Ferns are found at sites in New York, Michigan, Tennessee, Alabama, Ontario, Oaxaca, Chiapas and Hispaniola. Ontario has the bulk of populations north of Mexico. In this province the fern has been reported at more than 100 sites, mostly on the Niagara Escarpment, with about 75 of these believed to still exist.


Hart’s-tongue Fern grows on calcareous rocks in deep shade on slopes in deciduous forest. Most Ontario occurrences are in maple-beech forest. Established plants can grow in exposed, rocky crevices and on outcrops, but moist, mossy areas seem to be essential for spore germination and early plant development.


Populations of Hart’s-tongue Fern in Ontario are relatively secure, making the province an important refuge for the plant in North America.

In Ontario, threats to the species include logging, quarrying, development, competition from invasive plants, trampling on Escarpment trails and collecting for transplanting into gardens.


Hart’s-tongue Fern is listed as a species of Special Concern under Ontario’s Endangered Species Act. Although species of Special Concern do not receive legal protection under this act, about half of the known sites in Ontario are on public land, where they receive some protection. In particular, the Niagara Escarpment is protected, in part, by the Niagara Escarpment Plan.

What You Can Do to Help the Hart’s-tongue Fern

  • The Ministry of Natural Resources tracks species at risk such as the Hart’s-tongue Fern. You can use a handy online form to report your sightings to the Natural Heritage Information Centre. Photographs with specific locations or mapping coordinates are always helpful. nhic.mnr.gov.on.ca
  • Report any illegal activity related to plants and wildlife to 1-877-TIPS-MNR (847-7667).
  • Private land owners have a very important role to play in species at risk recovery. You may be eligible for stewardship programs that support the protection and recovery of species at risk and their habitats.
  • Volunteer with your local nature club or provincial park to participate in surveys or stewardship work focused on species at risk.
  • Invasive species seriously threaten many of Ontario’s species at risk. To learn what you can do to help reduce the threat of invasive species, visit: ontario.ca/invasivespecies; www.invadingspecies.com; www.ontarioinvasiveplants.ca; and, www.invasivespecies.gc.ca.
  • The Carolinian forests of southern Ontario support an amazing diversity of plants and wildlife, including many species at risk. Carolinian Canada is working to help recover species at risk and their habitats. For more information, visit: www.carolinian.org/SpeciesHabitats.htm.

Did you know?

Two varieties of Hart’s-tongue Fern are recognized, one European and the other American.

Did you know?

Hart’s-tongue Fern has very specific habitat requirements, making transplantation and artificial propagation difficult.

The Endangered Species Act

Contact your local ministry office

Often the best source of local information on species at risk is your nearest ministry office. Call with your questions or concerns.