Polystichum species - Shield-ferns

There are two Polystichum species.

Polystichum setiferum Soft Shield Fern has pinules with obvious, showy, acuminate teeth. There are big, prominent distal-facing 'thumbs' which lie along the midrib with no gap and angle between the base of the pinule and its proximal edge is clearly obtuse.

Because the pinule 'sits' on the midrib and the angle 'leans back', think of settee (as an aid to setiferum).

Polystichum aculeatum Hard Shield Fern has smaller pinule teeth and no prominent 'thumbs' and base of pinule veering away from the midrib. The angle between pinule base and proximal edge is clearly acute. The 'acute' angle prompts the epithet aculeatum.

Of the two Polystichum species, this is the more common one in Lanarkshire.