This fern has narrow, undivided fronds up to 60 centimetres long, and its common name was inspired by the tongue-shaped leaves. The spore-producing bodies, or “sori”, occur in short rows on the underside of the fronds. The fronds grow in clusters from short, creeping rhizomes that are covered in cinnamon-coloured scales.
Like most ferns, the hart’s-tongue fern can be found growing in moist soil and damp cracks in old walls. It is a common species in Europe, with the exception of the far north.