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Lichens in History

Somewhat authentic reference to lichens is found in the writings of the Greek philosopher Theophrastus (382-287 B. C.), a pupil of Aristotle. He gives us imperfect descriptions of Old Man's Beard (Usnea barbata) and Roccella tinctoria. Dioscorides, a Greek physician, and the founder of botany, who flourished in the first and second centuries, and also Gaius Plinius, a Roman naturalist (23-79), who perished in the eruption which destroyed Pompeii, both wrote of lichens which may have been those described by Theophrastus. It is not improbable, however, that they were speaking of Marchantia or some other liverwort. The fact that lichens had few qualities which rendered them particularly conspicuous, caused them to be largely neglected by the early botanists. They are not as a rule striking in colour, size, or form and they have no marked useful or harmful properties. The incentive which led to the early study of plants was a desire to find properties which would be of use in medicine or in the household, therefore the early herbalists gave their attention to plants with real or imaginary medicinal properties.

The lichens which could yield a dye were among the first to receive attention. Roccella tinctoria is supposed to have yielded the blue and purple dye of the Old Testament (Ex. XXV:4). The dye called oricello, was certainly in use before the first century of our era. The knowledge of the dye was lost after the fall of the Roman Empire, but in 1300, Federigo, a Florentine of German parentage, accidentally rediscovered the method of preparing and using it. He is said to have achieved great success, and to have become the head of a distinguished family, the Oricellari, Roccellari, and Rucellai. From which we have orseille, the name of the dye material, and Roccella, the name of the genus of which Roccella tinctoria is a member. A blue litmus solution is produced by fermenting this lichen. It may be turned red by adding an acid and then turned blue again by adding an alkali as ammonia or limewater. For this reason it serves as a test for acid and alkaline substances.