NOT a tree fern?

NO - 'Tis a fern tree.
I don't know the names, "Latin" or English for more than, literally 2-3 ferns; but Polypody is one of them.  We didn't, in reality, learn them "at our mother's knee" but on walks with Mam as kids.  I could almost take you to the length of hedge she first pointed it out to me.  I suspect she, accidentally, misinformed us in that she told us that it only grew on (Can't remember now which) the inside or outside of field hedges. 

According to the Wildlife Trust:-
"The common polypody is a medium-sized fern that is characteristic of damp, shady gorges and banks in woodlands, as well as rocks, walls and mossy branches.  It can also survive in quite dry conditions and is ideal for gardens - plant it in shade under trees, or on walls or gravelly areas for attractive cover."  
I don't think it's read the book as I've seen it in Dry stone walls, up dry trees, and up moist trees, like this one.

The extra is a cloud I spotted sneaking through/lurking in the gap twixt Skiddaw and Blencathra on my way to rendezvous with Jerra for our Jerraday; which again has been moved from its customary Thursday.

BTW marra - it's weell short o' bed-time & the score is 4951.
;¬)

I added the 2nd extra as a reference.  I spotted these en route back to the car and wondered what the point was; we might see - later?

Addendum:-
I found a list of "12 ways to kill a tree stump."
# 8 quoth thusly;-
"8. How To Kill A Tree Stump With Copper Nails
I have read enough places that copper nails do kill trees but it just takes a long time like over a year. If you have time for the copper nails to slowly poison your stump then go for it. I haven’t tried this yet because I don’t want to wait a year to see if it actually works. I’ll just use goats.
To kill a tree stump with copper nails all you do is hammer a ring of nails around the stump into the live tissue of the tree. Then just wait and your tree stump should slowly get poisoned and die in the next year or so."