278 PROCEEDINGS OF THE AMERICAN ACADEMY 



Tribe III. VERRUCARIACEiE, Fr. 



XXVII. CONOTREMA, Tuckerm. 



Perithecia mostly solitary, horny, black, at first pertuse, becoming 

 at length open, with a coarctate, inflexed margin, including a depressed 

 nucleus, which is elevated at the centre into a somewhat marginate 

 disk. Thallus crustaceous. 



C. urceolatum, Tuckerm. Crust thin, smooth, rugose-rimose, glau- 

 cous-white, bordered by a black line ; perithecia scattered, at first cov- 

 ered by the crust, finally superficial, conoidal, white-pruinose. Lecidea 

 urceolata, Ach. Lichenogr. p. 671. Ach. Syn. p. 27. Pyrenula ente- 

 roleuca, Spreng. in Hals. Lick. N. Y. I. c. Thelotrema enieroleuca, 

 Schwein. in Hals. I. c. Verrucaria enteroleuca, Spreng. Syst. 4, p. 243. 

 Tuckerm. Lich. N. E. I. c. Icon, Hals. I. c. t. 1, /. 1. 



Trunks. North America, Swartz. (ex Ach.). Pennsylvania, MuJil. 

 in herb. Willd. ! New York, Halsey. New England, very common. 

 Probably the Lecanora urceolata of Muhl. Catal., but the above-cited 

 specimen in the herbarium of Willdenow is without name. The Li- 

 chen appears to me an aberrant form of the present tribe. Thelotre- 

 ma ? atratum, Fee Crypt. Exot. t. 13, f. 4, seems to be distinguished 

 from Thelotrema precisely as the present genus (passing over the other 

 essential differences) is, by its black proper exciple, but the structure 

 of the nucleus in the former plant removes it from ours. 



XXVIII. VERRUCARIA, Pars. 



Perithecia hemispherical-globose, solitary, horny, black, closed, with 

 a simple or papilljEform ostiole ; becoming sometimes at length subscu- 

 telliform, or rarely inclosed in a thalline verruca. Nucleus gelatinous, 

 hyahne, deliquescent. Thallus crustaceous. 



* Saxi c ol ce . Crust somewhat tartareous. 



1. V. rwpes/m, Schrad. Crust tartareous-compact, contiguous, whit- 

 ish ; perithecia (small) entire, globose, somewhat sunk, umbonate with 

 the naked ostiole, at length collapsing and scutelliform ; nucleus hya- 

 line. Fr. Lichenogr. p. 436. Hook. Br. Fl. 2, p. 152. V. Schraderi, 

 Ach. Icon, E. Bot. t. 1711, /. 2. 



Rocks and stones (limestone). Pennsylvania, Muhl 



