ECONOMIC USES OF LICHENS — ^LLANO 407 



color panels illustrating the colors obtainable. These works estab- 

 lished their author as an authority, and he is the source of information 

 in later numerous and often unacknowledged studies. Westring's 

 system of the classification of lichen dyes distinguishes between lichen 

 dyes which impart color to pure water (essential pigments) and those 

 requiring certain treatment to yield color (preparable pigments). 

 Lebail (13) in 1853 and Lindsay (11) in 1854, as well as others, classi- 

 fied lichen dyes according to the color produced, recognizing, how- 

 ever, that color varied with treatment. 



History. — Of all the lichen dyes used by man, none has attained 

 greater historical and commercial importance than those of the 

 -Roccellaceae, variously known to the English as orchella moss, or- 

 chella weed, orchil paste or orchil liquor, to the French as orseille, and 

 to the Germans as persis. Orchil and cudbear are preparations of 

 lichens and not the actual plants. Lindsay (12) states that: 



We may practically regard Orchil as the English, Cudbear as the Scottish, 

 and Litmus as the Dutch name for one and the same (?) substance. The first 

 being manufactured in the form of liquid of a beautiful reddish or purple 

 colour; the second in the form of a powder of a lake or red colour; and the 

 third in that of small parallelopipeds or cakes of a blue color. The commercial 

 or trade designations of the dye-lichens depends upon the thallus being erect or 

 pendulous, cylindrical or shrubby or flat, crustaceous, foliaceous, and closely 

 adhering to the substrate. The former are "weeds" (Roccella) ; the latter are 

 "mosses" (Leca7iora and Pannelia). 



The attempt to combine trade names and utilitarian characteristics 

 with imperfectly known taxonomic features produced these peculiar 

 groupings of widely different species. 



Theophrastus and Pliny appeared to have been familiar with the dye 

 of the Roccellaceae, while a Biblical reference has their origin in the 

 "Isles of Elisha." During the Middle Ages the art of making this 

 dye fell into disuse, and it disappeared from the markets of the world, 

 until the seventeenth and eighteenth centuries, when it again took oii 

 the aspects of an industry, and the "weed" became an article of inter- 

 national exchange comparable to spices. Lindsay was particularly 

 interested in the commercial aspects of lichens. His recommenda- 

 tions for a fuller investigation of the subject throws some light on 

 the economic aspects of lichens in trade. He indicates that the field 

 is comparatively new, and open to many possibilities, especially if 

 the lichen resources of Scotland were exploited. "The speculation 

 (investment?) of substituting home for foreign dye lichens promises 

 to be remunerative as the roccellas have frequently reached the high 

 price of £1,000 per ton in the London market." In 1855 he reempha- 

 sized that "if commanders of ships were aware of the value of these 

 plants, which cover many a rocky coast and barren island, they might 

 with a slight expenditure of time and labor bring home with them such 



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