LICHENES. 75 



per lobules, orbiculate, or oblongo-rotundate, affixed by their 

 entire bases upon the thallus, by which too they are bordered. 



29. Nephroma. Thallus foliaceous, coriaceous or membra- 

 naceous, lobed. Apoihccia borne on proper lobules, orbiculate 

 or reniform, affixed by their entire bases on the inferior side 

 of the thallus, by which too they are bordered. 



30. Cetraria. Thallus foliaceous, cartilagineo-membrana- 

 ceous, lobate, laciniated. Apothecia orbiculate, obliquely adnate 

 by a part to the margin of the thallus, the rest free ; the disk 

 coloured, the border of the substance of the thallus. 



31. Gyrophora. Thallus foliaceous, coriaceous, fixed by 

 the centre. Apothecia orbiculate, sessile, covered by a dark 

 membrane, the border of their own substance, (not thallodal) ; 

 the disk usually marked with gyrose plaits. 



More anxious to make known the species of Irish Lichens than to 

 offer any opinion on the construction of Genera, I have limited myself 

 to Acharius's distribution, by no means presuming to imply that new 

 sub-divisions, lately proposed by distinguished botanists, will not prove 

 in time worthy of adoption. 



