[4] Ophioglossum lusitanicum is native to regions bordering the eastern North Atlantic Ocean in Mauritania, Macaronesia (excluding Cape Verde), Morocco, Portugal, France up to the Isles of Scilly and Channel Islands; all countries bordering the Mediterranean; the Caucasus region and has some records in India and Vietnam.

[5] The distribution in Britain is restricted to one small area of coastal heath on St Agnes, Isles of Scilly where it was discovered by John Raven in 1950.

It grows in short turf on Wingletang Down where some of the colonies are suffering from an increase of competitive grasses, gorse (Ulex europaeus) and bramble (Rubus fruticosus).

[6] Ophioglossum lusitanicum is listed on Schedule 8 of the Wildlife and Countryside Act 1981, and is within a Site of Special Scientific Interest (SSSI).

In its British populations, it favours thin, unshaded, peaty soils in south-facing localities.