88 



POPULAR HISTORY OF LICHENS. 



paratively few and expensive species now employed in the 

 manufacture of orchill, cudbear, and litmus."* "We cannot 

 specialize the results, but they were sufficiently encouraging 

 to warrant us in recommending the subject to the attention 

 of all who are likely to travel, at home or abroad, in locali- 

 ties which are rich in crustaceous and fruticulose Lichens, — 

 that is, in mountainous or maritime districts. We found 

 that the species most likely to yield valuable colorific results 

 are those growing on rocks, having a crustaceous, whitish, 

 warted, friable thallus; that, to a certain extent, colorific 

 quality is proportionate to the kind or degree of sorediiferous 

 degeneration of the thallus • that showy foliaceous species 

 are least likely to yield purple dyes, though they frequently 

 furnish yellowish, greenish, reddish, or brownish colouring 

 matters ; and that, short of actual experiment, it is impos- 

 sible to predicate colorific value, the colour of the thallus 



* The results were laid before the meeting of the British Association, at 

 Glasgow, in September, 1855, and before the Botanical Society of Edinburgh 

 on various occasions during the years 1852, 1853, and 1854 ; vide Edin. New 

 Philos. Journal, Oct. 1854, Jan. and July, 1855 ; ' Phytologist/ vol. iv. pp. 

 867, 901, 998, 1068, and vol. v. p. 179. Series of specimens, preparations, 

 and drawings, illustrative of the economical applications or uses of British and 

 Foreign Lichens (collected or made by the Author) will be found in the Na- 

 tional Industrial Museum for Scotland, and in the Museum of Economic 

 Botany, Koyal Botanic Garden, Edinburgh. 



