74 THE AMERICAN MONTHLY [Mar., 



1 Spores muriform, colored, Apo. patelliform 3. — Continued. 



3 Exciple paler than the disk 45 Heterothecium 



3 Ex. coal black 47 Buellia 

 a Apothecia diftbrm, rounded or oblong 4 



4 In a diftbrm rounded or stellate pseudo-stroma 56 Arthouia 



4 Black in a difform pseudo-stroma 57 Mycoporum 

 a Apothecia orateriform 60 Acolium 

 a Apo. globular immersed 5 



5 In the thallus 63 Endocarpon 

 5 In thalline warts 66 Staurothele 

 5 In a stroma 67 Trypethelium 

 5 Solitary or confluent prominent 70 Pyrenula 

 5 Sol. or confluent turbinate 71 Pyreiiastrum 



b Apothecia lirellseform 53 Graphis 



b A.po. urcoelate 37 Thelotrema 

 b Apo. patellaiform 1 



1 Exciple paler than the disk 45 Heterothecium 



1 Ex. coal black 47 Buellia 

 b Apothecia scutellseform 2 



2 Apothecia blackened, gyro.se plicate thallus attached to the 



subtrate by a single point 13 Umbilicaria 



2 Thallus crustaceous, squamulose, granulose, parenchymatous 



22 Pannaria 



2 Thallus dark green 27 Coll em a 



2 Th. lead colored 28 Leptogium 

 b Apothecia rounded or oblong 3 



3 Difform in a white stroma 54 Chiodecton 

 3 In a difform pseudo-stroma 57 Mycoporum 



3 In a rounded or stellate pseudo-stroma 56 Arthonia 

 b Apothecia immersed 4 



4 In the thallus 63 Endocarpon 

 4 In thalline warts 67 Trypethelium 

 4 lunate 69 Verrucaria 

 4 Prominent 70 Pyrenula 



Spores oblong. 

 1 Oblong only a 

 1 Oblong ovoid b 

 1 Oblong ellipsoid c 

 1 Oblong fitsiform d 

 a Colored 1 



a Colorless or decolorate 2 



a Fucescent 22 Pannaria 



1 Thallus fruticulose 7 Schizopelte 



1 Th. foliaceous squamulose or crustaceous 63 Endocarpon 



1 Th. uniform z 



z Apothecia patella;tbrm 45 Heterothecium 



z Apo. rounded or oblong x 



X Apo. concave black in a white stroma 55 Glyphis 



X Apo. in a difform rounded or stellate pseudo stroma 



56 Arthonia 

 X Apo. black in a difform pseudo-stroma 57 Mycoppruni 



1 Apo. crateriform, stipitate 61 Calicium 



2 Colorless or decolorate y 



y Thallus squamsaeform or monophyllous 64 Normandina 



