CLASS XXII. ORDER V. 135 



of the frond, each opening by a little mouth : seeds 

 enclosed in cells: frond membranous, somewhat 

 crustaceous, of a determinate figure ; so united to 

 the substance of the receptacles as to appear of a 

 piece, excepting a little difference of colour. 57. 

 2 — miniaiu?n, (hidden lichen) peltate, pale, with 

 spread-lobes. 



C. Rece/iiacles formed of the frond itself ivith 

 ivhkh it agrees in substance and colour : seeds 

 (excepting of the sphaerophoron) enclosed infiro" 

 per cells. 



1. Recefitacles comfiound^ either pierced or gaping, 



Thelotrema. Receptacles compound ; the 

 outer ones wart-like, elevated, of the substance of 

 the crust ; inner ones somewhat globular, with a 

 concave disk : frond a firm, continued, indetermi- 

 nate crust. 57. 2 — pertusus^ (crust lichen) warts 

 hemispheric with 1 or 2 pores. 



3. Receptacles nearly globular^ closed ; at length 

 bursting. 



Sphaerophoron. Cellules nearly globose, each 

 enclosing a roundish ball of naked compact seeds, 

 which turns to black powder, and is discharged by 

 the torn orifice, leaving the cellule hollow and 

 empty : frond shrubby, branched, solid, rigid, tar- 

 tarous or minutely fibrous within ; with a smooth 

 cartilaginous coat. A very elegant genus resem. 

 bling corol. 57. 2 — globiferus, (seed-ball lichen) 

 shrubby branched cylindric brownish smooth. 



IsiDiuM. Receptacle of the seeds terminal, sub- 

 discoid, solid, various in thickness, covered with, 

 and shining through, the crust of the papillae of 

 the frond, which at length bursts, and each recepta- 

 cle appears coloured and partly exposed : globules 

 also either terminate each papilla or are nearly ses- 



