A few years ago, when Chris and I moved into this property, the garden was...well, let's say it needed a little t.l.c. As the clearance work got under way I was pleased to find a solitary Hart's Tongue Fern Phyllitis scolopendrium (= Asplenium scolopendrium) in a crevice. Now, some 7-8 years later, there must be a dozen along the banks of the stream - the Bell Brook - which forms one border of the garden. Unfortunately, following prolonged and heavy rain yesterday, during which time the stream rose by over two feet, most of the plants are now under water!
In my 1923 copy of "Potter's Cyclopaedia of Botanical Drugs" recommends a preparation of this plant for 'removing gravelly deposits in the bladder'; I'll bear that source in mind. It will save a trip to Travis Perkins.