534 GBAPHIDACEAE. 



9. Arthonia platygraphidea Nyl. Act. Soe. Sci. Fenn. 7: 483. 1863. 



On bark, New Providence, on Soldier's Road, and Cat Island, vicinity of The 

 Bight : Florida ; Cuba ; Porto Rico ; Mexico ; Brazil. 



10. Arthonia atrata (Fee) Muell. Arg. Mem. Soc. Phys. Hist. Nat. Geneve 



29 s : 59. 1887. 



Graphis atrata Fee, Essai Crypt. 35. 1824. 



Not Arthonia atrata Tuck. Genera Lich. 222. 1872. 



On bark, New Providence : tropical America. 



2. ARTHOTHELIUM Mass. 

 1. Arthothelium macrothecum (Fee) Mass. Eic. Lich. Crost. 55. 1852. 



Arthonia macrotheca Fee, Suppl. Essai Crypt. 42, pi. 40, f. 18. 1837. 



On bark, Abaco, at Marsh Harbor, and New Providence, at Soldiers' Home : 

 widely distributed in tropical regions of both hemispheres. 



Family 2. GRAPHIDACEAE. 



Spores four- to many-celled. 

 Spores colorless. 



Spores with cylindrical cells. 1- Opegrapha. 



Spores with lens-shaped cells. 2. Graphis. 



Spores brown. 3. PhaeograpJns. 



Spores muriform-multilocular. 



Spores colorless. 4. OrapJiina, 



Spores brown. 5. PhaeograpMna. 



I. OPEGRAPHA Hurnb. 



Growing on bark. 



Spores four-celled. 1. O. atra. 



Spores six-celled. 



Spores 2-4 w wide. - O.vulgata. 



Spores 7-9 , wide. 3. O. varia. 



Growing on rocks. 

 Spores four-celled. 



Thallus white. 4 - - calcarea. 



Thallus gray, greenish or brownish. 5. 0. saxlcola. 



Spores six- to eight-celled. 



Thallus some shade of brown. 



Thallus thin and continuous. 6. O. isalicllina. 



Thallus of medium thickness, rimulose-areolate. 7. O. bahamcnsts. 



Thallus slate-gray. 8. O. columbina. 



1. Opegrapha atra Pers. in Usteri, Ann. Bot. 7: 30. 1794. 



On bark, New Providence, at Soldiers' Home : widely distributed. 



2. Opegrapha vulgata Ach. Meth. Lich. 20. 1803. 



On bark, New Providence : widely distributed in temperate regions. 



3. Opegrapha varia Pers. in LTsteri, Ann. Bot. 7: 30. 1794. 



On bark, New Providence: cosmopolitan. 



4. Opegrapha calcarea Turn, in Smith, Eng. Bot. pi. 1690. 1807. 



Opegrapha Chevallieri Leight. Ann. Mag. Nat. Hist. II: 13: 90. 1854. 

 On limestone, Conception Island : Europe ; California ; Cuba. 



5. Opegrapha saxicola Ach. Syn. Lich. 71. 1814. 



On limestone, New Providence : Europe ; California ; Cuba. 



