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Local Lichens

Don Smith

The Ramalina lichens are immediately recognisable by the way they stick out a cluster of thin branches at right angles to the rock or bark surface on which they grow. After the crustose and foliose (leafy) lichens they form the third group, the fruticose lichens. Unfortunately for this group, unlike the first two which only have the upperside exposed to the elements, air pollution and acid rain can affect all the surfaces. As a result, following the rise in air pollution during the last century, Ramalinas in lowland England have declined drastically, many now being extremely rare.

One particular species, Ramalina capitata, has the tips of the branches covered in a powder (soredia). According to the British Museum identification bible, the species was reported sometime in the 19th century from the Grampian mountains in Central Scotland and considered dubiously British. In 1985, I reported a Ramalina from Salton churchyard, 4km south of Edstone, but couldn’t name it. However, a few months ago an expert friend called in at Salton and declared, in great amazement, that this was R. capitata. This then is the first indisputable British record. I recently had a telephone call from Prof. Mark Seaward at Bradford University since sketching out this article, who told me that he too had found this species in Lincolnshire a few years ago.

The Society outing to Hutton Buscel was a success in terms of numbers. Eight or nine turned up, the majority from Scarborough and everyone could see what went on. It was rewarding to find half a dozen Ramalina siliquosa lichens on one headstone. This species is more at home on the coast above highwater mark and is grazed by sheep in the Shetlands and North Wales where it is known locally as ‘sea ivory’. Perhaps the most abundant and conspicuous lichen seen was Haematomma ochroleucum, with its pure white orbs, almost covering the east side of many sandstone headstones. Its generic name derives from the blood-red fruits when found fertile. Apart from just one thallus, all was var. porphyrium, lacking usnic acid which would have given it a pastel green colour.

The east end of the south facing church wall was covered in sheets of Lecanora pannonica. It was in late 1991 when I discovered the tower and masonry of Weaverthorpe church covered in a light grey lichen speckled with tiny clumps of grey/black powder. Samples sent to Dr. Brian Coppins, an international expert at Edinburgh Botanical Gardens, proved impossible to identify. He sent samples to a Dr. Brodo, a visiting American expert in Helsinki who named it as above. Apparently, this species has only been found in churchyards, here and in America.

[There is a report and species list of the Society’s visit on the web at hbuscel.htm]

There have been many successful studies during the last century using lichens to estimate sulphur dioxide air pollution due to the fact that they are long lived, are surface dwellers and are sensitive to air and water borne pollutants. As SO2 levels have decreased over recent decades, ammonia is increasing in importance as an air pollutant in Europe. The mapping of this air borne chemical using lichen surveys has been undertaken recently in a number of countries including the Netherlands, Denmark, Italy, Spain, Germany and Belgium. In addition, at least 50% of lichens contain organic compounds with varying antibiotic and curative properties. Cetraria islandica, for instance, common on Scottish Highland heaths and known as ‘Iceland Moss’, is a rich source of protolichesterinic acid, active against cancer tumours. It is a staple food for caribou and reindeer and in Germany is sold as a tea, as a hangover cure and also in cough sweets. A chemical firm in Slough is currently screening hundreds of British lichens for novel pharmaceutical products.

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