AETHONIACEAE. 533 



Order 3. GRAPHIDALES. 



Apothecla without an exciple. Fam. 1. Ahthoxiaceae. 

 Apothecia with an exciple. 

 Thallus without a cortex. 



Apothecla solitary. Fam. 2. Geaphidaceae. 



Apothecla typically Imbedded in a stroma. Fam. 3. Chiodectonaceae. 



Thallus with an upper cortex. Fam. 4. Dikinaceae. 



Family 1. AETHONIACEAE. 



Spores two to many-celled. 1 Arthonla 



Spores murlform-multUocular. 2. ArthotJielium. 



1. AETHONIA Ach. 



Spores four- to six-celled. 



Apothecla some shade of red. 1. A. gregana 



Apothecla brown or black. 



Apothecla orbicular or dlfCorm. 



Apothecla about 0.3 mm. in diameter. 



Spores with cells of equal size. 2. A. cModectella. 



Spores with end-cell enlarged. 3. A. cinereopruinosa. 



Apothecla over 0.6 mm. in diameter. 



S(f>ores with cells of equal size. 4. A. polymorpha. 



Spores with one or both end-cells enlarged. 5. A. complanata. 



Apothecla linear, more or less branched. 6. A. interducta. 



Spores eight- to sixteen-eelled. 

 Spores 22-32 x 7-11 «. 



Apothecla fulvous, 0.1 mm. wide. 7. A. fissminea. 



Apothecla chestnut, 0.3-0.5 mm. wide. 8. A. septiaepta. 



Spores 50-75 xl4-23». 



Apothecla orbicular. 9. A. platygraphidea. 



Apothecla linear and branched. 10. A. atrata. 



1. Arthonia gregaria (Weig.) Koerb. Syst. Lich. Germ. 291. 1855. 



Sphaeria gregaria Weig. Obs. Bot. 43, pi. S, f. 10. 1772. 

 Arthonia cinnalarina Wallr. Crypt. Germ. 1: 320. 1831. 

 On bark, Stocking Island, Exuma Chain : — cosmopolitan. 



2. Arthonia chiodectella Nyl. Flora 52: 125. 1866. 



On bark. New Providence : — Florida ; Louisiana ; Texas. 



8. Arthonia cinereopruinosa Seliaer. Bnum. Lich. 243. 1850. 

 On bark. New Providence : — North America ; Europe, 



4. Arthonia polyni6rpha Ach. Syn. Lich. 7. 1814. 



On bark, Great Bahama, New Providence, Great Exuma : — widely distributed in 

 tropical regions of both hemispheres. 



5. Arthonia complanata Fee, Essai Crypt. 54. 1824. 



On bark, Great Bahama, at Pinder's Point : — widely distributed in tropical and 

 subtropical America and in New Zealand. 



6. Arthonia interducta NyL Act. Soe. Sei. Fenn. 7: 496. 1863. 



On bark. Stocking Island, and Cay north of Wide Opening, Exuma Chain : — 

 Florida ; Anegada Island ; Nicaragua ; Brazil ; Hawaiian Islands. 



7. Arthonia fissurinea Nyl. Flora 68: 447. 1885. 



On bark. Great Bahama, near Rolletown : — Florida. 



8. Arthonia septisepta Nyl. Flora 69: 104. Hyponym. 1886. Nyl. apud Willey, 



Synops. Arth. 11. 1890. 



On bark. New Providence : — Florida ; Cuba. 



This species is very closely related to the common Arthonia conferta (Ffie) Nyl., 

 differing only in having the apothecla spuriously margined and the spores eight- 

 celled instead of six-celled. 



