OF ARTS AND SCIENCES. 257 



New York, Halsey. Pennsylvania, Muhl. — /?, limestone ; New York, 

 Torrey. Pennsylvania, Muhl. 



6. L. contigua., Fr. Cr. at first contiguous, glaucous-white ; apoth. 

 produced from the crust ; disk thick, horny, very black, at first glaucous- 

 pruinose, with a thick, discrete, plano-cupular, obtusely marginate, car- 

 bonaceous exciple. Fr. Lichenogr. p. 298. 



Rocks and stones (granite), and often tinged ochraceous by the oxide 

 of iron, in the mountains of New England. 



7. L. variegata, Fr. Cr. at length areolate, glaucescent ; the black, 

 somewhat fimbriate hypothallus here and there prominent ; apoth. pro- 

 duced from the crust, depressed, at first and often persistently glaucous- 

 pruinose, black within ; disk from urceolate becoming explanate, and 

 dilated, with a persistent, at first thin, coarctate, at length obtusish mar- 

 gin. Fr. Lichenogr. p. 303. 



Maritime granite rocks ; Arctic America, Fries. 



8. L. lapicida, Ach. Cr. at length areolate-verrucose, from glau- 

 cous becoming cinereous-white ; apoth. superficial, produced from the 

 cortical layer, sessile, not pruinose, horny and cinerascent-black within, 

 with an even, naked disk, and a thin, at length flexuous margin (or, the 

 margin disappearing, finally confluent and irregular). Fr. Lichenogr. 

 p. 306. 



Rocks and stones (granite), in mountainous districts ; New England. 

 New York, Halsey. Pennsylvania, Muhl. Arctic America, Rich. 



9. L. atro-alha, Ach. Cr. somewhat areolate (the areolae commonly 

 discrete, verrucaeform), opake, fuscous, and grayish-white; apoth. pro- 

 duced from the hypothallus, (small,) the obtuse margin scarcely discrete 

 from the naked, at length somewhat umbonate disk. Fr. Lichenogr. 

 p. 310. 



Rocks and stones (granite) ; New England. New York, Halsey. 

 The crust variable, and often nearly obsolete. 



10. L. panceola, Ach., Fr. Areolte of the crust verrucose, gray, 

 variegated with rufescent tubercles ; apoth. produced from the hypo- 

 thallus ; exciple cupular, with a persistent, obtuse margin ; disk always 

 plane, very black, csesious-pruinose, white within. Fr. Lichenogr. x>- 

 314. — /?. ohscurata, Fr. ; areolae thinner, applanate, somewhat con- 

 tiguous, fuscescent. Fr. I. c. L. ohscurata, Schcer. ! Spicil. p. 130. 

 Tuckerm. Lich. N. E. I. c. 



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