224 THELOTREMA. 



than that of the T. album of Nyl. Syn. N. Caled. p. 36, from the 

 T. microporum of the same place. Myriotrema, Fee Exs. p. 

 103, with its two supposed species, covers probably precisely 

 the same ground as Montague's species, and is an older ar- 

 rangement ; but Montague first really understood and described 

 the plant. 



2. T. lathrceum, Tuckerm. in lilt. ; thallus thin-membrana- 

 ceous; glaucescent; apothecia very minute, immersed, open; 

 the softish, white interior exciple discrete from the thallus, bor- 

 dering with an elevated, rounded margin, a blackening disk ; 

 the exterior exciple deficient. Spores oblong ; 6-9-locular ; ^J 

 mic. 



On various trees, Cotoosa river, Florida, Austin. Apo- 

 thecia barely O mm -, 1 in diameter: those of the next follow- 

 ing species, reach O mm -, 8. 



3. T. subtile, Tuckerm. ; thallus membranaceous, smoothish, 

 becoming chinky, or at length powdery ; glaucescent, cineras- 

 cent now quite dark, or white ; apothecia immersed becoming 

 superficial, small to minute, depressed-hemispherical' and dif- 

 form, open ; interior exciple discrete, lax, its white, thin margin 

 which encloses the flat, blackening, white-pruinose disk much 

 surpassed by the exterior exciple. Spores fusiform- oblong ; 8- 



16-locular; ^ mic. Suppl 1, I c. p. 426. T. bicinctulum, 



Nyl. Licli. N. Caled. in Ann. Sci. 4, 15, p. 46. 



On various trees, New England (Frost), Tuckerrnan I. c. 1858. 

 Virginia, Tucker man. South Carolina, and Georgia, Ravenel. 

 Alabama, Beaumont. Texas, Eavenel ; Hall. 



4. T. granulosum, Tuckerm. ; thallus cartilagineous, smooth, 

 verrucose-granulate ; glaucescent ; apothecia small, depressed- 

 hemispherical, adnate, granulate, with an ample aperture ; the 

 margin of the exterior exciple elevated and at length acute ; 

 the depressed disk black, concealed by a white, crustaceous, 

 finally perforated veil. Spores oblon g- ellipsoid ; 6-10-locular; 

 ^ m ic. Suppl. 1, 1. c.p. 426. 



On Bald Cypress, Louisiana (Hale), Tuckerinan I. c. 1858. 



Florida, Austin. The proper exciple, constituting the interior 



part of the exterior one, brown or blackening j often at length 

 more or less visible at the margin. Apothecia of about the 

 size of those of T. subtile. 



