KEY TO THE ARRANGEMENT. 5 



22. P ANN ARIA. Apothecia either simply scutellaeform, or 



the disk also bordered by a proper margin (zeorine) 

 or the thalline margin obsolete, and the proper margin 

 alone exhibited (biatorine). Spores ovoid or oblong, 

 simple, or more rarely bi-quadrilocular, or very rarely 

 muriform - plurilocular, fuscescent, or decolorate. 

 Thallus monophyllous, or multifid, or, most often, 

 squamulose, becoming crustaceous. 



Fam. 6. COLLEMEL Thallus frondose-foliaceous, more or 

 less gelatinous when moist j becoming squamulose, or 

 even crustaceous ; lead-coloured, or blackish-green j the 

 hypothallus almost always obsolete. Gouimia, without 

 exception characteristical of the family, and conditioning 

 its whole structure. 



Sub-Fam. 1. LICHINEI. Thallus fru tic ulose or alectorise- 

 form; the gonimia constituting an axis, which finally 

 breaks up; or crowded together into a more regular 

 layer, between the cortical, and the at length parenchyma- 

 tous medullary. Apothecia globose, or variously irreg- 

 ular. 



23. EPHEBE. Apothecia globose. Spores oblong-ellipsoid, 



simple, uncoloured. Thallus filiform, much branched, 

 blackish-green ; the never concatenate gonimia finally 

 somewhat stratified. 



24. LICHINA. Apothecia terminal, globose. Spores ellip- 



soid, simple, uncoloured. Thallus fruticulose, brown- 

 ish-black ; the concatenate gonimia distinctly strati- 

 fied. 



Sub-Fam. 2. EUCOLLEMBI. Thallus foliaceous or squamu- 

 lose, or even crustaceous j very rarely fruticulose j the 

 gonimia disposed most often in necklace-like chains, 

 which are dispersed, more or less, in a gelatinous 



