August has been recommended as the best month for collecting dye-lichens: i.e. just after the season of greatest light and heat when the accumulation of acids will be at its maximum.
Some of the acids found useful in dyeing occur in the thalli of a large number of lichens, many of which are too scantily developed to be of any economic value. Thus salazinic acid which gives the effective yellow-brown dye in Parmelia conspersa was found by Zopf in 13 species and varieties. It has since been located by Lettau[1313] in 72 different lichens, many of them, however, with poorly developed or scanty thalli, so that no technical use can be made of them.
h. Lichen Colours and Spectrum Characters. In a comparative study of vegetable colouring substances, Sorby[1314] extracted yellow colouring matters from various plants distinguished by certain spectrum characters. He called them the “lichenoxanthine group” because, as he explains, “these xanthines occur in a more marked manner in lichens than in plants having true leaves and fronds.” Orange lichenoxanthine he found in Peltigera canina, Platysma glaucum, etc., when growing well exposed to the sun. Lichenoxanthine he obtained from the fungus Clavaria fusiformis; it was difficult to separate from orange lichenoxanthine. Yet another, which he terms yellow lichenoxanthine, he obtained most readily from Physcia (Xanthoria) parietina. The solutions of these substances vary according to Sorby in giving a slightly different kind of spectrum. He did not experiment on their dyeing properties.
F. Lichens in Perfumery
a. Lichens as Perfumes. There are a few lichens that find a place in Gerard’s[1315] Herball and that are praised by him as being serviceable to man. Among others he writes of a “Moss that partakes of the bark of which it is engendered. It is to be used in compositions which serve for sweet perfumes and that take away wearisomeness.” At a much later date we find Amoreux[1316] recording the fact that Lichen (Evernia) prunastri, known as “Mousse de Chêne,” was used as a perfume plant.
Though lichens are not parasitic, the idea that they owed something of their quality to the substratum was firmly held by the old herbalists. It appears again and again in the descriptions of medicinal lichens, and still persists in this matter of perfumes. Hue[1317] states in some notes to a larger work, that French perfumers extract an excellent perfume from Evernia prunastri ([Fig. 59]) known as “Mousse des Chênes” (Oak moss), and it appears that the plants which grow on oak contain more perfume than those which live on other trees. The collectors often gather along with Evernia prunastri other species such as Ramalina calicaris and R. fraxinea, but these possess little if any scent. A still finer perfume is extracted[1318] from Lobaria pulmonaria called “moss from the base of the oaks,” but as it is a rarer lichen than Evernia it is less used. Most of the Stictaceae, to which family Lobaria belongs, have a somewhat disagreeable odour, but this one forms a remarkable exception, which can be tested by macerating the thallus and soaking it in spirit: it will then be found to exhale a pleasant and very persistent scent. These lichens are not, however, used alone; they are combined with other substances in the composition of much appreciated perfumes. The thallus possesses also the power of retaining scent and, for this reason, lichens frequently form an ingredient of potpourri.
b. Lichens as Hair-powder. In the days of white-powdered hair, use was occasionally made of Ramalina calicaris which was ground down and substituted for the starch that was more commonly employed.
In older books on lichenology constant reference is made to a hair-powder called “Pulvis Cyprius” or “Cyprus powder” and very celebrated in the seventeenth century. It was believed to beautify and cleanse the hair by removing scurf, etc. Evernia prunastri was one of the chief ingredients of the powder, but it might be replaced by Physcia ciliaris or by Usnea. The virtue of the lichens lay in their capacity to absorb and retain perfume. The powder was for long manufactured at Montpellier and was a valuable monopoly. Its composition was kept secret, but Bauhin[1319] (J.) published an account of the ingredients and how to mix them. Under the title “Pulvis Cyprius Pretiosius” a more detailed recipe of the famous powder was given by Zwelser[1320], a Palatine medical doctor. The lichen employed in his preparation, as in Bauhin’s, is Usnea, but that may include both Evernia and Physcia as they are all tree plants. He gives elaborate directions as to the cleaning of the lichen from all impurities—it is to be beaten with a stick, washed repeatedly with limpid and pure water, placed in a linen cloth and dried in the sun till it is completely bleached and deprived of all odour and taste.