Polystichum aculeatum, the hard shield-fern,[1] is an evergreen fern native to Europe.

It is most abundant in upland regions of the British Isles and western France, where it benefits from the combination of mild winters and moist summers, but also occurs more locally across most of Europe except northern Scandinavia, northern Russia; in the Mediterranean region it is confined to high altitudes.

The fronds are stiff and hard-textured, bipinnate (single-pinnate on small, young plants), with the pinnae opposite on the stalk.

The round sori occupy two rows on either side of the midrib of each pinnule and are covered by a centrally-attached, umbrella-like indusium with fringed edges.

[4][5] It is found in the counties of Down, Antrim and Derry in Ireland,[6] throughout the British Isles and Europe except for the northern countries.