Lichen (Teloschistes chrysopthalmus)
|Size||Lobe width: up to 2 mm (2)|
Tuft height: up to 1 cm (2)
Classified as Critically Endangered in Great Britain, Extinct in Northern Ireland, and is classified as Threatened by the preliminary European Red List for macrolichens. General protection is afforded by the Wildlife and Countryside Act 1981 (3).
This lichen is a 'fruticose' (3) or 'shrubby' species (4); it is composed of branching lobes that form small orange tufts, which are almost spherical in shape (5) and have spiny projections (2). The name of this genus, Teloschistes means 'split ends' and refers to the body of the thallus(2).
At present, this lichen is currently not known from UK, but it is widely thought that it could reappear (6). The most recent records are from Cornwall in 1997 and 1998, and Devon in 1966 (3), but it has since disappeared from both of these areas (6). It is believed to be extinct in Northern Ireland, but is still recorded in south-western Ireland (5). Elsewhere, it is widespread in warm areas of both hemispheres (5).
Found on well-lit twigs on shrubs and small trees, and prefers sheltered and sunny areas (3). In the UK, known habitats include old orchards and hedgerows, but it has also been seen growing on fence posts and other timber structures near the coast (3).
Lichens are remarkable organisms; they consist of an alga and/ or a cyanobacteria and a fungus living together in a symbiotic association (5). A general rule is that the fungal component of a lichen is unable to live independently, but the alga may live without the fungal partner as a distinct species (5). Many lichens are known to be very sensitive to environmental pollution, and they have been used as 'indicators' of pollution (4).
This species produces fruiting bodies called 'apothecia' which occur on short stalks. These contain a bag-like structure called an 'ascus', which contains spores. Because the fruiting bodies are produced only by the fungal partner of the lichen, after the spore has dispersed it must acquire cells of the correct alga or it will be unable to survive (2).
The decline in the range of this species is thought to be the result of air pollution, the loss of old orchards and hedgerows, and the use of fertilisers (3). The hawthorn bush on which the species lived on at the last known Devon site was removed in order to widen a footpath at the site (3). A further potential threat is botanical collecting (3).
As a UK Biodiversity Action Plan Priority Species, Teloschistes chrysophthalmus has a Species Action Plan, which guides conservation efforts. Plantlife, the wild plant conservation charity is the 'lead partner' for this lichen, and has included the species in its 'Back from the Brink' campaign. The Action Plan aims to maintain and enhance any re-discovered populations, and if possible, to reinstate the species at two former sites by the year 2005 (3).
For more on British lichens see: Dobson, F. (2000) Lichens: an illustrated guide to the British species. The Richmond Publishing Co. Ltd., Slough.
Information authenticated by Plantlife, the wild plant conservation charity:
- Alga: a collection of taxonomically unrelated groups that share some common features but are grouped together for historical reasons and for convenience. They are of simple construction, and are mainly photoautotrophic, obtaining all their energy from light and carbon dioxide, and possess the photosynthetic pigment, chlorophyll A. They range in complexity from microscopic single cells to very complex plant-like forms, such as kelps. Algal groups include blue-green algae (cyanobacteria), red algae (rhodophyta), green algae (chlorophyta), brown algae and diatoms (chromista) as well as euglenophyta.
- Cyanobacteria: a group of bacteria that are able to photosynthesise and contain the pigment chlorophyll. They used to be known as ‘blue-green algae’. They are thought to have been the first organisms to produce oxygen; fossil cyanobacteria have been found in 3000 million year old rocks. As they are responsible for the oxygen in the atmosphere they have played an essential role in influencing the course of evolution on this planet.
- Fungus: fungi are one of the taxonomic kingdoms, separate from plants and animals. They obtain nutrients by absorbing organic compounds from the surrounding environment.
- Spores: microscopic particles involved in both dispersal and reproduction. They comprise a single or group of unspecialised cells and do not contain an embryo, as do seeds.
- Symbiotic: relationship in which two organisms form a close association, the term is now usually used only for associations that benefit both organisms (a mutualism).
- Thallus: type of simple plant body that does not have stems, leaves and roots.
- National Biodiversity Network Species Dictionary (May 2002) http://www.nhm.ac.uk/nbn/
- Dobson, F. (2000) Lichens: an illustrated guide to the British species. The Richmond Publishing Co. Ltd., Slough.
- UK BAP (May 2002): http://www.ukbap.org.uk
- Allaby, M. (1998) Oxford Dictionary of Plant Sciences. Oxford University Press, Oxford.
- Church, J. M., Coppins, B. J., Gilbert, O. L., James, P. W. & Stewart, N. F. (1996) Red Data Book of Britain and Ireland: lichens. Volume 1: Britain. The Joint Nature Conservation Committee, Peterborough.
- Duckworth, J. (2002) Pers. comm.