KEY TO THE ARRANGEMENT. 9 



Fam. 1. CLADONIEI. Thallus two-fold, a vertical one 

 (podetium) ascending from a horizontal, squamulose, or 

 granulose one j the latter now obsolete. 



39. STEREOCATJLON. Apothecia patellseform, brown, at 



length convex and the margin excluded (ceplialoid) 

 solid. Spores fusiform or acicular, 4-plurilocular, 

 colourless. Thallus fruticulose, erect, solid (podetia), 

 clothed more or less with granules, passing now into 

 fibrils ; horizontal thallus granulose, or obsolete. 



40. PILOPHORUS. Apothecia cephaloid, solid, black. 



Spores ellipsoid, simple, colourless. Podetia simple, 

 or but little branched, originally solid, granulate; 

 horizontal thallus granulose. 



41. CLADONIA. Apothecia mostly cephaloid, variously 



coloured (not black). Spores ovoid-oblong, simple, 

 colourless. Podetia fistulous, either simple, and cup- 

 shaped or funnel-shaped, or at length very much 

 branched ; rarely club-shaped ; the horizontal thallus 

 squamulose, or rarely granulose, or obsolete. 



Fam. 2. CCENOGONIEI. Thallus horizontal, conferva-like. 



42. CGENOGONIUM. Apothecia patellseform. Spores fusi- 



form-ellipsoid, simple or bilocular, colourless. Thal- 

 lus composed of jointed filaments densely inter- 

 tangled, making a more or less determinate web. 



Fam. 3. LECIDEEL Thallus crustaceous; now lobulate, 

 or even, very rarely, caulescent j but, for the most part, 

 uniform ; adnate to the substrate. 



Sub-Fam. 1. B^EOMYCEI. Apothecia prolonged down- 

 wards into a stipe (stipitate). 



43. B^OMYCES. Apothecia patellaeform, or cephaloid ; 



the stipe now reduced, or disappearing. Spores ellip- 

 soid, or sub-fusiform, simple, or now bi-quadrilocular, 

 colourless. Thallus horizontal ; lobulate, or uniform. 



