Variolaria.] LICHENES. 169 



On calcareous stones, in the walls of old churches, &c. frequent ; 

 sometimes on plastered walls. /J. on brick walls, y. on limestone 

 rocks, Killarney, Sir T. Gage. 



4. V. glob alt/era, Turn, (globuliferous Variolaria) ; crust 

 orbicular somewhat tartareous tliickish glaucescent rugose 

 sprinkled all over with white soredia and surrounded by a 

 somewhat zonate border of various colours, apothecia large 

 spherical depressed at the apex where they at length burst 

 irregularly becoming scutelliform with a lacerated border, 

 powder white. Turn, in Linn. Trans, v. 9. p. 139. t. 10. /. 2. 

 Turn, and JBorr. Lick, Br. p. 60. Ach. Syn.p. 130. — V. glomu- 

 lifera, Ach. Lick. Univ. p. 322. t. 5. f. 9. — Lichen g lob u lifer its, 

 E. Bot. t. 2003. 



On old Oaks at Hurst-pierpoint, and on Beech-trees in the Sussex 

 Forests, Mr. Borrer. 



5. V. discoidea, Pers. (insipid zoned Variolarici); crust orbi- 

 cular somewhat tartareous tliickish glaucous- white surrounded 

 by ft zonate border of various colours, apothecia numerous flat 

 with a thick border, powder snowy-white. Turn, and Borr. 

 Lich. Br. p. 61. — V. amara, c. discoidea, Ach. Syn. p. 132. 

 — Lichen discoideus, Ach. Prodr.? E. Bot. t. 1714. — Dill. 

 Muse. p. 18./. 11. D. 



Common on the bark of trees, and, occasionally, on pales, walls, and 

 rocks. 



6. V. faginea, Pers. (bitter zoned Variolaria); crust orbicular 

 somewhat tartareous tliickish glaucous-white surrounded by a 

 zonate border of various colours, apothecia very abundant 

 convex with an obsolete border, powder snowy-white. Turn. 

 and Borr. Lich. llr. p. 64. — V. communis, b. faginea f Ach. 

 Syn. p. 130. — Lichen fagineus, Linn. — E. Bot. t. 1713. 



Common on the bark of trees, especially of old Beech, and on pales. 

 — " The intensely bitter taste of this Lichen distinguishes it from ever) 



ies hitherto discovere I. It is upon this circumstance, which we 



have never found to vary, that we have been induced to place our 

 chief reliance in making V. faginea and V. discoidea, distinct; for it 

 must not be dissembled that the\ are two plants which nearly agree in 

 almost even? other particular; and which have been confounded b) the 

 great majority of authors." Turn, and Borr. — M. Braconnol detected 

 in this and several other crustaceous Lichens, oxalic acid; inthepresenl 



plant in Mich abundance that 100 parts \ icldcd Is of lime, combined with 

 89. I of oxalic acid: and nearl\ tin- same quantity in several other CTU8- 

 taceOUfl Lichen^. And he remarks that the oxalate of lime heart the 

 same relation to the Cryptogamia as carbonate of lime to corals, and 



phosphate of lime to the bony structure of the more perfect animals. 

 It diminishes, however, gradually in the family of Lichens, in proportion 

 ai the Bpeciet lose their general crastai eons texture and approach more 



and more to the membranous or cartilaginous, although the latter 

 also contain a considerable quantity of salt- 1 M Braconnot Btr< 

 recom mended the adoption 01 I in the production of oxalic acid, 



1 i:.ii.i. v ri,ii tan*, v I-;, p 



