Clean air act

It was a mild and murky afternoon with cloud hanging heavy and the ground soft and soggy in the valley of the Cleddau Wen. Lichen were the star attraction here. This one is a fruticose lichen, a member of the genus Usnea, its nerve-like strands indicating pure air - the longer the better. Medicinally, it contains usnic acid which is effective against Strep and Staph bacteria.

On the trunk of the same birch tree I was thrilled to spot another lichen (extra 1) this time one of the foliose varieties belonging to the genus Lobaria and with the popular name Lungwort because its soft, damp, leafy frills resemble lung tissue. In the past it used to treat pulmonary complaints for that reason. It also produces an orangey-brown dye. Once common it's now confined to the westernmost parts of Britain but even here suitable locations such as this one are threatened by climate change and habitat destruction.

Both these lichens are indicators of excellent air quality but that's not to suggest that lichens are inevitably delicate and fragile. At the outset of the walk we crossed a village playing field with a line of concrete bollards along the edge. I noticed that each bollard had an individual pattern of crustose lichens decorating the surface, regardless of, or perhaps encouraged by, the bird poo and dog pee that accompanies them (extra 2).