Exciting fern

This is a frond from a Golden-scaled Male Fern, Dryopteris affinis subs. affinis. I have managed to confirm it as present within the nature reserve today and it is classed as 'scarce' within the county. The shape of the pinnules (leaflets), the very scaly stem and the shape of the doughnut-like indusia (protective covers for the spore-producing sori) are all diagnostic features. Such are the preoccupations of botanists!