|Ophioglossum azoricum in coastal grassland, Dooncarton, Co. Mayo|
C. Presl 1984
Ophioglossum azoricum is native to islands in the northern Atlantic Ocean and adjacent westernmost Europe from the Azores north to western France, the British Isles, Iceland and Greenland. It also occurs in the Toscana region of Italy.
This species mostly occurs on bare or shortly vegetated ground on exposed coastal clifftops. An exception to this habitat preference is populations in the New Forest, Hampshire where plants occur in tightly grazed damp grassland in a non-maritime setting.
The frond of Ophioglossum azoricum consists of a single, pointed leaf blade and a narrow pointed spore-bearing spike on a stalk. The spike has about 4-18 segments on each side, each of which opens up when ripe to release spores. The sterile blades are broadest near the middle and taper towards both ends.
This taxon is sometimes treated as a subspecies of Ophioglossum vulgatum, as Ophioglossum vulgatum ssp. ambiguum (Coss. & Germ.) E.F. Warburg.
This species has a chromosome number of 2n=c.480.
-  Ophioglossum azoricum at Schede di botanica
-  Ophioglossum azoricum at Online Atlas of the British and Irish Flora
- Löve Á. (1983) Flora of Iceland.Almenna Bókafélagid
- Lid J, Lid DT, Elven R. 1994 Norsk flora. 6th edition. Oslo: Det Norske Samlaget
- Stace, Clive (1997). New Flora of The British Isles, second edition. Cambridge: Cambridge University Press
- BSBI map: Distribution of Ophioglossum azoricum in the British Isles
- "The Ferns (Filicopsida) of the British Isles" — Ophioglossum azoricum — by L. Watson and M. J. Dallwitz.
- West Highland Flora: species account for 'Ophioglossum azoricum
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