534 



GEAPHIDACEAE. 



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 Eico ; Mexico ; Brazil. 



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



29^ 59. 1887. 



GrapMs atrata F6e, Essai Crypt. 35. 1824. 



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



On bark, New Providence : — tropical America. 



2. AKTHOTHELIUM Mass. 

 1. Arthothelium macrothecum (Pee) Mass. Eie. Lich. Crost. 55. 1852. 



Arthonia macrotheca Pee, Suppl. Essai Giypt. 42, pi. 40, f. 18. 1837. 



On bark, Abaeo, at Marsh Harbor, and New Providence, at Soldiers' Home ; — 

 widely distributed in tropical regions of both hemispheres. 



Family 2. GEAPHIDACEAE. 



Spores four- to many-celled. 

 Spores colorless. 



Spores with cylindrical cells. 1. Opegrapha. 



Spores with lens-shaped cells. 2. Graphis. 



Spores brown. 3. Phaeographis. 



Spores muriform-multiloeular. 



Spores colorless. 4. OrapMna. 



Spores brown. 5. Phaeographina. 



1. OPEGRAPHA Humb. 



Growing on bark. 



Spores four-celled. 1. 0. atra. 



Spores six-celled. 



Spores 2—4 « wide. 2. O. vulgata. 



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



Growing on rocks. 

 Spores four-celled. 



Thallus white. 4. 0. calcarea. 



Thallus gray, greenish or brownish. 5. O. saxicola. 



Spores six- to eight-celled. 



Thallus some shade of brown. 



Thallus thin and continuous. 6. O. isabelHna. 



Thallus of medium thickness, rimulose-areolate. 7. 0. Ijahamensis. 



Thallus slate-gray. 8. O. colunibina. 



1. Opegrapha 4tra 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 Usteri, 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. 



