CRYPTOGAMIA ALG.^. 817 



niated and lobcd at the extremitits. The upper 

 lurface is of a blue-grey, and fometimes a 

 whitifh afh-colour, uneven, ahd full of nume- 

 rous fmall pits, or cavities j the under fide is 

 black, and covered all over, even to the edges* 

 with Ihort fimple ha^^s, or radicles, Befides the 

 pits above-mentioned, the upper furface is alfo 

 frequently covered with minute farinaceous tu- 

 bercles. 

 The fhiclds are rarely produced ; they are of a 

 dark chefnut colour, moderately large when full 

 grown, with their margins turned inward, their 

 out -fides rough, pitted, and of the fame colour 

 as the leaves^ Sometimes fmall eminences, or 

 tubercles, are to be feen on the difc of the 

 fhields. 

 J^'arinaceous tubercles and mields are both found 

 upon the fame plant. But the old plants gene- 

 rally produce the (hields, and the young ones 

 the farinaceous tubefcies. The young ones 

 have alfo their leaves divided into wider and 

 more obtufe fcgmeats. 

 A variety of this Lichen fometimes occurs with 

 leaves tinged of a red or purple colour, called 

 by Ray^ Lichenoides arboreum 'purpurafcens, tenue 

 £lf Uve fcutellis majoribus. R, Syn. 73. 

 This Lichen is ufcd by finches, and other fmall 

 birdsj in conftruding the outfide of their cu- 

 rioufly-form'd nefts. 



G g g L. im° 



