y 



KEY TO THE ARRANGEMENT. 



ticulose, or pendulous ; sottish ; with a cottony 

 medulla. 



5. USNEA. Disk and thallus pale. Spores sub-ellipsoid, 



simple, colourless. Thallus fruticulose, or pendulous ; 

 mostly rounded ; alike on all sides ; with a double 

 medulla, the innermost woody. 



6. ALECTORIA. Disk coloured differently from the thal- 



lus. Spores ellipsoid, simple, or now muriform- 

 multilocular, brown, or, more often, decolorate. 

 Thallus fruticulose, or pendulous; mostly rounded; 

 alike on all sides ; cottony within. 



7. SCHIZOPELTE. Disk black, dilated and lobed. Spores 



oblong, 4-locular, blackish-brown. Thallus fruticu- 

 lose, terete. 



Fam. 2. PARMELIEI. Thallus horizontal, foliaceous, dif- 

 ferently coloured and normally fibrillose beneath, where 

 it is without veins or cyphels. [See PeltigereL] Karely 

 ascendant, evernisefbrm j more rarely alectoriaBform. 



8. SPEERSCHNEIDERA. Apothecia scutellaeform. Spores 



oblong, 2-4-locular, colourless. Thallus terete-com- 

 pressed, dichotomously very much branched, and 

 intertangled, forming rounded, appressed patches; 

 fibrils obsolete. 



9. THELOSCHISTES. Apothecia scutellseform ; the disk 



yellowish - orange. Spores polar -bilocular [in an 

 exotic species quadri-locular] colourless. Thallus 

 foliaceous, or now ascendant and everniaeform ; mostly 

 yellowish. 



to. PARHELIA. Apothecia scutellaeform ; the disk mostly 

 thin. Spores ellipsoid, and oblong, simple, colourless. 

 Thallus foliaceous; or now everniaeform ; or even 

 alectoriaeform ; rather membrauaceous. 

 11. PHYSCIA. Apothecia scutellseform ; the disk thickish. 



