OF ARTS AND SCIENCES. 267 



Sect. I. Apothecia superficial, destitute of a thallinc margin. 



1. O. varia, Pers., Fr. Crust somewhat leprous, indeterminate 

 (rarely innate in the matrix) ; apothecia superficial, tumid ; margins of 

 the entire exciple at length distant, becoming thin, or disappearing; 

 disk somewhat plane, at first subpruinose, blackish within. Fr. Lichen- 

 ogr. p. 364. O. cymhiformis^ Schczr. ! Spicil. 1, p. 50. — «. pulicaris, 

 Fr. ; apoth. rather elliptical ; disk a little concave, margin inflexed. Fr. 

 I. c. O. vulvella, Ach. — /5. notha, Fr. ; apoth. rounded ; disk turges- 

 cent, and often obliterating the margin. Fr. L c. Opegrapha, Ach. 

 Graphis curvula, Ehrh. Tuckerm. Lich. N. E. I. c. — /. signata, Fr. ; 

 apoth. elongated ; disk broad, plane, margin evanescent. Fr. ! I. c. 

 Opegrapha, Ach. Lichen hehraicus, Hoffm. O. cymhiformis, var. he- 

 braica, Schczr. ! Spicil. p. 330, part. — 8. diaphora, Fr. ; apoth. elon- 

 gated, both ways rather attenuated ; margin somewhat persistent. Fr. 

 I. c. Opegrapha, Ach. 



Thick bark of oaks and other trees, and degenerant on dead bark 

 and wood, and stones ; New England. New York (« and /5), Halsey. 

 Pennsylvania (a and /3), Muhl. 



2. O. atra, Pers., Duf. Cr. innate in the matrix ; apoth. emergent 

 superficial, slender, shining, acute ; margin of the somewhat entire ex 

 ciple thin ; disk linear, canaliculate, naked, horny within. Fr. Lichen 

 ogr. p. 366. — a. stenocarpa, Fr.- ; apoth. very long, semicylindrical 

 flexuous ; discrete, or reticulate-anastomosing, or maculaeform and ir 

 regular. Fr. I. c. Schcer. ! Spicil. p. 48. 0. stenocarpa, denigrata 

 vulgata, 8f epipasta, a, Ach. — /5. ahhreviata, Fr, ; apoth. abbreviated 

 irregular, often radiately disposed. Fr. I. c. O. depressa, (|- 0. epi 

 pasta, y, 8, Ach. — y. macularis, Fr. ; apoth. dilated into somewhat 

 radiate, immarginate maculae, and confluent. Fr. ! I. c. Arthonia as- 

 troidea, 8f A. Swartziana, Ach. — 8. siderella, Fr. ; cr. fuscescent ; 

 apoth. acute, opake, somewhat innate and here and there erumpent. 

 Fr. I. c. Opegrapha, Ach. O. rufescens, a. rubella, Schcer. ! Spicil. 

 p. 50 (e Fr.). 



Smooth bark of trees ; New England. New York (a and y), Halsey. 

 Arctic America (O. epipasta, /5), Rich. 



3. O. herpetica, Ach., Fr. Cr. innate in the matrix, at length erum- 

 pent, and verruculose ; apoth. emergent, elliptical or obtusely lanceo- 

 late, opake (somewhat ocellate or marginate by the white thalline ver- 

 rucse) ; margins of the entire exciple thin ; disk canaliculate, naked, 



