892 On Lichens. [No. 1 19. 



us, it is the product of warm climates on maritime rocks in almost every 

 part of tlie world, and always growing with. B. fueiformis, DeCand, which 

 might almost lead to the suspicion, that they were mere varieties of each 

 other. The Canary Islands formerly yielded this Lichen in abundance, 

 whence it has been called Canary weed ; but so great has been its consump- 

 tion of late years, that the best quality of it, whose average price is £200 

 per ton, (about 1-12 per seer, or Rs. 70 per maund,) has become extremely 

 scarce, and what is commonly imported from other countries, is not worth 

 £30 the ton, or Rs. 10 per maund, (a trifle more than three pence a pound, 

 or 4 As. per seer.) The English blue broad cloths are first dyed with Ar- 

 chill, which gives their peculiar lustre and purple tint when viewed in a 

 certain light. — English Flora, vol. y.p. 221. 



M. Robiquet has separated the colouring matter of this vegetable. 

 The new and singular product which he has obtained has a very sweet 

 flavour, is easily soluble in water, colourless, crystalizes in beautiful flat 

 quadrangular prisms ; by means of a moderate heat it may be volatilized 

 without decomposing, and does not acquire the colouring property till it 

 has undergone successively the action of ammonia and of common air. — 

 Silliman's Journal, vol. 18, in English Flora, vol. v. add. and corrig. p. 10. 



Note. — Eoccella fuciformis, DeCand, is said by Dr. Royle, (Illustr. vol. i. 

 p. 438,^ to be more widely diffused than R. tinctoria, being found in Europe, 

 Brazil, as well as in Ceylon and the Peninsula of India, whence several 

 specimens have been sent to the Royal Asiatic Society ; but it is far infe- 

 rior in quality, containing indeed hardly any colouring matter. 



Dr. Ure in his Dictionary of Arts and Manufactures, details under the 

 article Archil, the different modes by which it may be rendered useful, and 

 the reader who wishes to be acquainted with them cannot do better than 

 consult the Dictionary. I may observe, that the Chulchulera of Hindoostan 

 belongs to the Genera Borrion or Evernia, which are both in the same 

 group with RoccELLA, (the UmhilicariecB,) and closely allied to it in exterior 

 characters. 



Evernia Prunastia, Ach. 



"Was brought into use in Glasgow by the late Lord Dundonald, and 

 employed (during the war) instead of gum in calico-printing, it afterwards 

 fell into disuse as a very inferior substitute for that BxticXe.— English Flora, 

 vol. V. p. 224. 



The next useful species noticed by Hooker is Bamalina Fraxina, Ach. 

 which has been used in Glasgow for the same purpose as the Evernia 

 Prunastia, {Flora, vol. v. p. 225) ; and from the apparent number of species 

 of this Genus in the Himalayas, it might be turned to advantage. 



