Usnea articulata String-of-sausage Lichen

Usnea articulata is very sensitive to sulphureous atmospheric pollution and was extremely rare in Britain throughout most of the 20th Century when sulphur dioxide pollution was common. As air has become cleaner it has undergone a remarkable recovery and is now locally common in parts of south-western Britain. It produces a conspicuous, long thallus, up to a metre in length, which hangs down like a drape from well exposed trees. In West Glamorgan it is frequently found festooned on well-lit Larch trees, along with other Usnea species, but it is also found on deciduous trees such as Oak and Alder. The branches of the thallus become constricted and swollen in such a way as to resemble a string of sausages, particularly near the points of attachment, and it is sometimes called the String-of sausage Lichen. It probably relies on exposed, windy sites to facilitate dispersal and it appears to be expanding its range in upland areas of West Glamorgan.

Listed by Alan Orange in Flora of Glamorgan (Wade et al, 1994).