Hart’s-tongue Fern

Harts Tongue Fern

(Asplenium scolopendrium)


  • Distinguishable from other Canadian ferns by its long, strap-shaped fronds
  • Usually grows in rocky areas, particularly on limestone rock outcrops in maple-beech forest
  • “Established plants can grow in exposed, rocky crevices and outcrops, but moist, mossy areas seem to be essential for spore germination and early plant development”. (ROM)


Special Concern Provincially and Nationally


Found in northern hemisphere, and is broadly split into European variety and American variety. American Hart’s-tongue ferns are found at disparate sites in New York, Michigan, Tennessee, Alabama and Ontario. Ontario has bulk of the North American populations having been reported at more than 70 sites mostly on the Niagara Escarpment.


Although populations of Hart’s-tongue Fern in Ontario are relatively secure, the populations here represent an important refuge for the species since its populations elsewhere are doing poorly.  Threats to this species in Ontario include logging, quarrying, development, competition from weeds and trampling from hikers on Escarpment trails.


  • Niagara Escarpment Plan protects public lands on the Niagara Escarpment, where approximately half of all known Hart’s-tongue populations occur


Royal Ontario Museum: Hart’s-tongue Fern

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