Philosophical transactions, Vol. L. Part II. For the year 1758. / Giving some account of the present undertakings, studies, and labours, of the ingenious, in many considerable parts of the world.

by Various; Royal Society

5. Lichenes foliacei scutellati.

Such as consist of a more lax and flexible matter, formed into a foliaceous appearance, having the parts of fructification in the form of scutellæ.

Some of the plants of this division are interspersed with the former in some of the systems of botanic authors. In general this division contains the whole first series of the second order of lichenoides in Dillenius; the first division of the second series, and the latter part of the second division, of the same: it comprehends the lichenes imbricati and umbilicati of Linnæus; and many of the placodium of Hill.

The plants of this order are many of them not less common in England than the foregoing, on rocks, stones, old pales, trees, &c. Some adhere very closely to what they grow upon, and seem to be only foliaceous about the edges: others adhere but loosely, and are much expanded and divaricated, so as to form something like ramifications.

It was remarked, from Linnæus’s observation, that one of the crustaceous lichens was scarcely ever found growing but upon limestone rocks. On the contrary, the same author has observed of a foliose lichen belonging to this order, that it will thrive on all kind of rocks but limestone rocks. This species[106] Dillenius calls The common grey-blue pitted lichenoides. It is very common with us upon trees, old wooden pales, &c. as well as upon rocks and stones. It is the usnea cranii humani of the old materia medica. Linnæus adds, that it will dye a purplish colour.

Hither likewise must be referred the cork or arcel[107], which is used by the Scotch, and others, to dye a purple or scarlet colour. The preparation of it is by powdering, and making it into a mass with urine. Parkinson tells us[108] the poor people in Derbyshire scrape it from the rocks, and make the same use of it. Mr. Ray[109] adds to this account, that the Welch, who call it kenkerig, have long been acquainted with this property, and have it in common use. The colour from this moss is but very dull; but if the same methods were taken to improve it, as have been with the orchel, it would undoubtedly be rendered much better, and more durable. Linnæus relates[110], that there is an immense quantity of this moss about the rocks of the isle of Aland in the Baltick; where the good women themselves make a yellow dye with it from a simple decoction of the plant, without the addition of any saline article. He adds, that those, who would heighten the colour, add a small quantity of roucou[111] to the decoction.

Professor Linnæus tells us, that the Gothlanders manufacture a yellow dye from the common curled lichenoides with yellow leaves and plates[112]. He adds, that it is a celebrated medicine in the esteem of the country people, as a specific in the jaundice[113]. Helwingius, in the Supplement to the Flora Prussica, affirms, that this moss will tinge paper and linen of a lively carnation colour, which too will stand the test of being exposed to the open sun for a long time without fading. It seems very probable, however, that he must mean some other plant of this genus, as Dillenius tells us he made the experiment unsuccessfully.

Sweden affords a moss of this order, which, as far as hitherto appears, seems to be unknown to former botanists, and which Linnæus says will dye a deep purple colour[114].