Lichens

Upon this herbless rock a small grey Lichen

Did fix her home

She came with meek intent, to bless her stern and sterile place of rest;

And presently her gentle sisters followed,

Some vestal white, and some in robes of brown,

And some in yellow vestures, labouring all

At the same work, with tiny cups held out

To catch the rain-drops, and with mattocks small

To pierce the rock

And well did they effect

Their destined purpose.

There are many industries on Dartmoor that have simply vanished mostly due to modern technical advances and declining demands. One such being lichen gathering which although not a booming industry did provide much needed income to some of the moor folk. In a similar light there was another natural resource which was gathered on Dartmoor – moss. But it is lichens were are concerned with here. Samuel Rowe gives the following account of the one-time tradition of lichen gathering on Dartmoor:

“In September, 1843, the host of the Saracen’s Head (now the Two Bridges Hotel), informed me that he had often been employed to receive the moss collected from the rocks in the neighbourhood, and to send it to Plymouth for exportation. At Trowlsworthy, on the southern borders of the moor, the warrener gave me a similar account, in June, 1843, stating that although the women and children, who gathered the lichen, were obliged to use a kind of chisel to detach it from the rocks, they could procure as much as would pay them at the rate of two shillings a day… Lyson relates that in the years from 1762 to 1767, inclusive, Mr. Davey collected from the rocks and tors of Dartmoor nearly one hundred tons of lichen tartarea. Many tons of the lichen perella were collected in the neighbourhood of Okehampton, about twenty years ago.“, p.275.

In 1834 a C. Dean wrote in the Farmer’s Magazine that during the summer months the poor folk of the moor would collect Orchella lichens. A dye manufacturer from northern England employed agents to collect the lichen for which they paid the gatherers between 3½d and 4½d per pound. In today’s terms that would now equate to around £13.34 a pound which is not bad for a days works. He also remarked how having taken the lichens from an area the gatherers would also disperse seeds onto rocks which never had a lichen presence. p.450. For centuries another ‘friend’ of lichens has been the tin miners who through their activities have created artificial rock faces which became home to the lichens.

Today lichen dyes are not used in commercial dying processes as modern synthetic dyes are cheaper to use. Having said that there are some traditional home-based dyers who still use the old techniques of dye making using lichens.

So first of all what is a lichen? According to the Natural History Museum they consist of; “two or more partners that live together symbiotically, with both of them benefiting from the alliance. One partner is a fungus. The other is either an algae (usually a green alga) or a cyanobacteriul, which is sometimes called a blue-green alga although it is more closely related to a bacteria than algae.“

One of the main lichens collected by the women was the Lichenoides saxatile more commonly known as the Cupthong. The optimum time for gathering this was after a spell of rain, the main reason being that during dry weather the lichen is very brittle. This would then be sold to the cloth dyers who would completely dry it out, crush it into powder form and then steep it in urine or a solution of tin in aqua fortis (nitric acid). This would then produce a vivid scarlet dye which initially was used in the manufacture of serge cloth and later to produce the cloth which made the British Army’s famous red coats.

Other mosses that were collected were the Lecanora tartae (cudbear lichen)  and Lecanora parella (crab’s eye lichen) which both produced a royal purple dye. Cudbear is the actual name of the dye first produced in 1758 by Dr. Cuthbert Gordon. It has also been referred to as Lunar Lichen due to the fact that it resembles the craters on the moon. In order to make a yellowish brown dye the Parmelia saxatilis (grey crottle lichen) and Parmelia omphalodes lichens were collected. These two were probably the most widely used of all the lichen dyes, partly due to the fact that they were widely used in Harris Tweed production. The  Lichen perellus would when processed produce a grey/red dye known as Parelle and was used in making litmus paper and often known as the ‘Dyers’ Lichen’.

In days of yore and before the NHS many types of lichens were used medicinally, looking at the state of the NHS maybe this should be something worth learning. Quite often there was a correlation between the shape of the lichen and the resemblance to parts of the human body which could be cured by it. What has to be my favourite of all Dartmoor’s lichen is the Dartmoor Matchstick or Piskie Cup, this lichen contains usnic acid which can be used to make anti-bacterial agents, anti-inflammatories and anti-analgesics amongst other things.

Dartmoor lichens face many challenges today and the sad fact is that lichens can take ages to grow as shown by Baring Gould’s comments; “There is a granite post I often go by. It was set up just seventy years ago, and on it the largest golden circle of the Physica parietina has attained the diameter of an inch.”, p.250. It is estimated that Map Lichen (Rhizocarpon geographicum) which can be found on may of Dartmoor’s granites grows at the meagre rate of 1 millimetre a year. Knowing this growth rate can be useful when trying to date the age of a stone artefact upon which the lichen grows. Should there be a patch of Map Lichen upon say an old granite post which has a diameter of 4 centimetres then in theory it’s been there at least 40 years. This method of calculation was first introduced in the 1950s and is known as Lichenometry.

The main factors that effect the lichens are air pollution and the growth of lichens can be used as a indicator as to the purity of the air. Another cause for concern is the siltation of water courses especially when this occurs upstream. The reduction of livestock grazing numbers on the moor is a kind of two-edged sword. Firstly the nutrients in the dung found where livestock numbers congregate can enhance the growth of some lichens. Conversely the presence of associated ammonia can cause a decline in some of the rarer lichen who thrive in nutrient poor conditions. There is also the suggestion that recreational activities such as rock climbing, bouldering and letterboxing can also have an effect on lichen populations. This is due to the lichen populations being damaged on rock faces, boulders and clitters where these activities take place. Fire can also take its toll, anyone that has visited an area following swaling or a brush fire will notice how the rocks appear to be bleached white. This is because all the lichens and mosses have been burnt away. Ironically although lichens are very susceptible to fire it is said that some of them can withstand a 1,000 rad exposure to nuclear radiation, every day for two years (400 rads would kill a human).

The main species of lichen that have particular conservation importance on Dartmoor are: Byroria smithii, Orange Fruited Elm Lichen, Graphina paulciloculata, Pertusaria melanochlora, Porocyphus kenmorensis, Schismatomma graphidioides, the String of Sausage Lichen, Golden Hair Lichen, Collema fragrans and Pannaria sampaiana. All of these species range from being seriously endangered, endangered, vulnerable or threatened with many coming under the protection of the Wildlife and Countryside Act of 1981.

This is a very brief overview of Dartmoor’s lichens as this is such a vast and complex subject to cover and is best studied by the in-depth publications and websites that are currently available – see HERE. The reason I have posted this was because I came across the very short passage that referred to the lichen gatherers. Sadly there is very little further information on this small scale industry which certainly belongs to the heritage of the moor.

Baring Gould, S. 1982. A Book of Dartmoor. London: Wildwood House.

Dean, C. 1834. Agricultural Reports – The Farmer’s Magazine – Vol. 1. London: Joseph Robertson