1895.] MICROSCOPICAL JOURNAL. 67 



b Th. fruticulose, disk and thalus pale, — Continued. 



4 Th. compressed or sub-1'olliaceous, cartilagineous 2 Eamalina 

 4 Th. rounded, alike on all sides with a double medulla, the 



inner-most woody 5 Usnea 



b Th. alectoriffiform 1 



1 Apothecia scutellseform 10 Parmelia 



1 Apo. angulate-patelljeform passing into lirelkcform 



52 Xylographa 

 b Th. caulescent 1 



1 Apo. patellieform and cephaloid 46 Lecidea 



1 Apo. unknown, thallus attached to substrate by root-like 



branches, th . densely cottony within Siphula 



b Th. crustaceous 1 



1 Apo. scutellseform 31 Lecanora 



1 Apo. globular, difform opening by pores, sp. large 33 Pertusaria 

 1 Apo. patelheform 2 

 2 Thallus squamulose, lobulate granulose; earth and rock 

 lichen reduced and disappearing ; sp. minute and very num- 

 erous 44 or 48 Biatora 

 2 Th, uniform, spores various 45 or 49 Heterothecium 

 2 Th. often caulescent apo. horny, th. lobulate, or filiform 



46 or 50 Lecidea 

 2 Th. lobulate, or uniform 47 or 51 Bueilia 



b Th. depressed 1 



1 Disk and thallus pale 2 Eamalina 



1 Disk colored dilierently from the th. to the tips or margins of 

 which the apo. are attached 3 Cetraria 



b Th. foliaceous 1 



1 Thallus rather membranous 10 Parmelia 



1 Th. peltate, hypothallus deficient, apo. indicated mostly by 



an ostiole, but emerging scutellasform 19 Endocarpiscum 



1 Th. clothed beneath with a nap-like hypothallus 21 Physma 

 1 Th. attached to the substrate by a single point, apo. subglo- 



bose 26 Omphalaria 



1 Apothecia blackened, gyrose plicate 13 Umbilicaria 



1 Thallus mostly dark green, gonimia mostly concatenate 



27 Collema 

 1 Th. mostly lead-colored, cortical layer distinctly parenchy- 

 matous 28 Leptogium 

 b Th. frondose 1 



1 Apothecia scutellaeform, marginal 17 Erioderma 



1 Apo. orbicular, innate 18 Solorina 



b Th. granulose 1 



1 Apo. sub-globose, immersed or superticial and explicate 



25 Pyrenopsis 

 1 Apo. patellaeform or cephaloid . 44 Biatora 



1 Apo. cephaloid, solid, black with podetia 40 Pilophorous 



b Th. lobulate 1 



1 Apo. scutellseform Omphalodium 



1 Apo. becoming zeorine 31 Lecanora 



1 Apo. stipitate 43 Baeomyces 



1 Apo. sessile a 



a the exciple paler than the disk 44 Biatora 



a the exciple cx)al black 46 Lecidea 



a the exciple coal black 47 Buellia 



1 Apo. immersed in thalline warts c 



c Paraphyses distinct 65 Segestria 



c Paraphyses obsolete 66 StaurotUele 



