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Hart's-tongue Fern

   Photo: Bill Crins

Features: Hart's-tongue Fern ( Asplenium scolopendrium) usually grows in rocky areas, particularly on limestone rock outcrops in maple-beech forest. It is distinct from other Canadian ferns due to the long, strap-shaped fronds. Typical of ferns, the undersides of the fronds have sporangia that form haploid spores. Spores are produced from May through August and can disperse widely from the parent plant. The spores germinate and grow into mature gametophytes, where egg and sperm unite to form a new diploid sporophyte plant. 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.

Status: Special Concern Provincially and Nationally

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

Threats: The range of Hart's-tongue Fern in North America is restricted and disparate. Populations of Hart's-tongue Fern in Ontario are relatively secure, whereas elsewhere in North America, the fern is not doing as well. Hence, Ontario represents an important refuge for the species in North America. In Ontario, threats to the species include logging, quarrying, development, competition from weeds and trampling from hikers on Escarpment trails.

Protection: 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. Hart's-tongue Fern has very specific habitat requirements, which means that management options such as transplantation and artificial propagation are not straightforward.

Text Sources: Austen 2000

Last Modified Date: September 2009

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