ACOTYLEDONS. LICHENS. Vcrrucaria. 43 



HAB. j(3. On slate and stones, frequent, Hopk. 



2. O. vulgata, crust between cartilaginous and mcmbranaceous 

 somewhat scaly smoothish greenish white, apothecia sessile 

 long or roundish, waved somewhat shining, with the disk very 

 narrow. Ach. Syn. Licit, p. 73. E. B. t. 1811. 



HAB. Bark of trees, common, Hopk. 



3. O. iriacutaris, crust very thin brownish black, apothecia mi- 

 nute much crowded roundish elliptical at length rugose irre- 

 gular, disk very narrow. Ach. Syn. Lich. p. 72. 0. epi- 

 phega, t. 2282. 



HAB. On the bark of trees, common, Hopk. 



Known by the apothecia being so closely crowded as to form !?"ish 

 black spots. 



SECT. II. HETERORENII. Apothecia sul simple, formed of a so- 

 litary perithecium (or external covering] including the fructi- 

 ferous mass. 



* Apothecia margined. 

 8. GRAPHIS. 



Universal receptacle crustaeeous, spreading, plane, adnate, uni- 

 form. Par rial recept. elongated, immersed in the thallus, 

 which forms a margin on each side the naked linear disk, not 

 covered by a membrane. (However correct this character 

 may be, the genus does not appear, in habit and general 

 external character, at all different from Opegrapha. 



1. Gr. scripta, crust membranaceous smooth somewhat shining 

 white or greyish brown bordered with black, apothecia half 

 immersed naked fiexuose simple or branched, disk very nar- 

 row, margin formed of the thallus raised membranaceous. 

 Adi. Syn. Lich. p.Sl. E. B. t. 1813 (Opegrapha scripla). 

 Lichen scriptus, Lightf. p. 800. 



HAB. On the smooth bark of trees occasionally, Lightf., Hopk. 



** Apothecia without any margin. 

 9. VERRUCARIA. 



Universal receptacle crustaceous, spreading, plane, adnate, uni- 

 form. Partial recept. globoso-hemisphserical, its base im- 

 mersed in the thallus, with a double coat} exterior subcarti- 

 laginous, thick (black), closing the upper half, tipped with a 

 small prominent orifice ; interior very thin, membranaceous, 

 including a subglobose cellular nucleus. 



1. V. ma?ira, crust very thin smooth much cracked very black, 

 apothecia very minute subglobose immersed the extremity 

 prominent umbilicated, nucleus blackish. Ach. Syn. Lich. 

 p. 95. E. B. ^.2456. 



HAB. Frequent on rocks on the Scottish coast ; as at Losic-mouth, 

 coast of Moray ; basaltic rocks ut Dunbur, Mr, JJorrcr and Hook. 



