OF ARTS AND SCIENCES. 387 



present, but also, it should seem, not advancing beyond it ; with appar- 

 ently a different thallus. As this last is described, and as G. verruci- 

 fonne is represented in the European specimens, we can scarcely avoid 

 considering the American lichen as, to appearance, and so far as we 

 yet know, distinct. 



CoLLEMA CTRTASPis, sp. nov. : thallo mediocri suborbiculari mem- 

 branaceo-cartilagineo rigido fusco-viridi subtus pallido laciniato-lobato 

 lobis mox angustatis subradiantibus lobulis adscendentibus granu- 

 lato-rugulosis ; apotheciis mediocribus disco convexo nigro-castaneo 

 nitido demum tumidulo marginem thallinum crassiusculum crenulatum 

 excludente. Sporee octonce in thecis subclavatis, incolores, subfusifor- 

 mes, tetrablastas (S-septatas) diam. 4- 6-plo longiores. On trunks near 

 the ground, in woods ; common in Southern Pennsylvania, Maryland, 

 and Virginia. Ohio, Lea. Illinois, E. Hall, in Hb. Lapham. North 

 Carolina, Rev. Dr. Curtis. South Carolina and Georgia, 3Ir. Ravenel. 

 Alabama, Mr. Peters. Thallus of middling size (from an inch to an 

 inch and a half in diameter) at first roundish, of cartilagineous-mem- 

 bi'anaceous, rigid, brownish or blackish green, expanded lobes, which 

 become at length much narrowed, and more or less radiant, passing 

 here and there into short, ascending, branch-like lobules, the dilated 

 and divided summits of which are wrinkled-plaited, and at length 

 densely granulate. Gonidia concatenate. Apothecia of middling size 

 (the largest often a line in diameter), the blackish-chestnut polished 

 disk soon becoming tumid, and quite excluding the originally thick 

 and crenulate thalline margin. Spores in eights, rather broad-spindle- 

 shaped (navicular-subfusiform, Koerb.), normally tetrablastish, with reg- 

 ular, mostly roundish sporoblasts, the three dissepiments, obscurely 

 more or less visible, four to six times longer than wide. The almost 

 monophyllous thallus of G. nigrescens becomes irregularly somewhat 

 lobed ("lobis cEespitoso-fasciculatis," Sommerf. Suppl. Fl. Lapp., p. 

 119) in G. aggregatum, Nyl. (G. Jasciculare, var. aggregatum, Ach.), 

 and passes, still further, in the present lichen, into at length laciniiform, 

 often radiant divisions. The present is sufficiently distinguished from 

 G. aggregatum by its different spores, but in this respect agrees better 

 with the European G. conglomeratum, Nyl. Syn. p. 115, t. 3, f 1 (C. 

 fasciculare, var. conglomeratum, Ach.), which differs especially in its 

 minute size ; the far less divided and less granulate thallus and more 

 entire apothecia ("margine tenui integerrimo," Sommerf 1. c.) being 

 perhaps less to be relied upon. — Growing with the present lichen in 



