Description
Usnea florida forms a bush of thin branches often ending in flat spore-producing discs and can grow to 10-20 cm long. This group of lichens can be easily identified by pulling back the outer sheath on the main stem. Usnea lichens have a cord running through the centre of the main stem. Lichen species which resemble Usnea do not have this white cord, and appear grey-green throughout.
Usnea lichen also contains potent antibiotics which can halt infection and are broad spectrum and effective against tuberculosis bacterial. Usnic acid (C18H16O7), a potent antibiotic and antifungal agent, is found in most species. This, combined with the hairlike structure of the lichen, means that Usnea lent itself well to treating surface wounds before sterile gauze and modern antibiotics. It is also edible and high in vitamin C.
Habitat
Found in broadleaf tree canopies. Prefers exposed, well-lit situations.
Status
Usnea is very sensitive to air pollution, especially sulphur dioxide. Under bad conditions they may grow no larger than a few millimetres, if they survive at all. Lost from at least eight sites recently in the core area of Devon. Threatened by nitrogen deposition and inappropriate woodland management.
Distribution
Southern and western British Isles.
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