Southern polypody
Polypodium cambricum
Family · Polypodiaceae · Harmless
The fern that grows on top of walls and tree trunks without taking anything from them, and does the opposite of all the others: it dries up in summer and comes back in September, when the rain starts.
Walls and rocks · Oak woods · Uplands · Streams and ditches
Also known asWelsh polypody, limestone polypody
How to tell it
A frond divided only once, into elongated alternate lobes along a green axis, looking like a broad comb. Beneath, round orange dots in neat rows, which are the spore cases. A creeping rhizome covered in brown scales, visible on the stone.
What it is confused with
Western black spleenwort
Asplenium onopteris
Polypody has a frond divided only once, into broad comb-like lobes; western black spleenwort has a frond divided three times, lace-like.
Open sheet →What it is for
The rhizome tastes sweet and was chewed and used in syrups in European folk medicine, which gave it the name sweet fern. It is not a parasite: it uses the tree or wall as a perch and feeds on rain and the matter gathered in the crack.
With documented traditional uses. Not a therapeutic indication and not a dose.