Wall ferns

Three tough fern species that remain green throughout the winter and survive all-year-round in a very inhospitable habitat. First up, wall rue (Asplenium ruta-muraria) thrives in the mortar of old walls and walls made of limestone. There are often fine displays on the shady side of churchyard walls and it often turns up on old masonry in the heart of cities.

 

Maidenhair spleenwort (Asplenium trichomanes) is an exceptionally graceful species and is also a lime-lover, so thrives in crumbling mortar wherever there is some shade and humidity.

Polypody fern (Polypodium vulgare) is an epiphyte – a plant that grows on other plants – and its natural habitat is on moss-covered branches of trees but in Weardale it often makes itself at home in between the capstones of drystone walls. It’s an evergreen fern and if you turn the fronds over even this late in the year you’ll often get a surprise – bright yellow clusters of sporangia on the underside of the fronds.

For a closer look at these hop over to http://beyondthehumaneye.blogspot.com/2009/11/polypody-fern-with-golden-sporangia.html