TV, L* Liiidsay on Canadian Lichens, 283 



Beeing that it is seldom a miscellaneous collection of licliens is 

 made in any part of Britain at all remote from the largest towns 

 without the discovery of interesting novelties. New species are 

 most likely to be met with amoog the very minute crustaceous 

 lichens which grow on rocks or trees, and which cannot be properly 

 studied without the aid of the microscope ; among species belong- 

 ing, for instance, to such genera as Lecidea, Lecanora, Graphis, 

 Opegrapha, Calicium. It is not to be expected that the tyro 

 should make these microscopical examinations or discoveries for 

 himself: he will probably require the assistance of some experi- 

 enced microscopist or lichenoligost. 



3. The applications of lichens to the arts are daily becoming 

 more numerous and important. New dye-lichens are being dis- 

 covered in India and the East. Among specimens of the latter 

 recently sent me from India, I have found species not hitherto 

 known to be of any practical use. Again recently the probability 

 has been shown, on good grounds, that a lichen — the Lecanora 

 esculenta of Pallas — was the Manna of the Bible. 



4. The colorific capability of a lichen, so far as regards a red 

 or purple dye of the nature of orchill or cudbear, may be readily 

 discovered by simply macerating the lichen — chopped into small 

 fragments or pulverised according to the nature of its thallus — 

 in a weakish solution of common hartshorn (the quantity not 

 much covering the lichen in a vial of any sort) — that is, the 

 " liquor ammonia " of druggists — allowing the mixture to stand 

 a few days in a warmish part of the house, aud shaking it fre- 

 quently, so as to expose the mass to the action of the air. Colo- 

 rific lichens of this class belong chiefly to the genera Roccella, 

 Umbilicaria, Romelia, and Lecanora. 



6. The colorific capability of a lichen, so far as regards other 

 colors — chiefly brown and yellow — may be easily ascertained by 

 simply boiling the lichen, chopped or pulverised as before, in a 

 small quantity of water. Colorific lichens of this class belong 

 chiefly to the genera Romelia, Sticta, Cetraria, &c. 



6. Whether and how much mucilage or starch a lichen con- 

 tains may be ascertained by the same means as last mentioned, 

 and allowing the mixture to cool, when it will gelatinise more or 

 less, if it contain much mucilage. Cetraria Islandica and some 

 of the Umbilicarise are illustrations. 



7. Contributions may also be made to our knowledge of the 

 economical applications of lichens by ascertaining whether any 



