CRYPTOGAMIA ALG^. S17 



niated and lobed at the extremities. The upper 

 lurface is of a blue-grey, and fometimes a 

 whitifh a(h-colour, uneven, and full of nume- 

 rous imall pits, or cavities •, the under fide is 

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

 with Hiort fimple hairs, or radicles, Befides the 

 pits above-mentioned, the upper furface is alfo 

 frequently covered with minute farinaceous tu- 

 bercles. 

 The Ihields are rarely produced ; they are of a 

 dark cheinut colour, moderately large when full 

 grown, with their margins turned inward, their 

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

 as the leaves. Sometimes Imall eminences, or 

 tubercles, are to be fcen on the difc of the 

 fhields. 

 Farinaceous tubercles and fhields are both found 

 upon the fame plant. But the old plants gene- 

 rally produce the {hields, and the young ones 

 the farinaceous tubercles. The young ones 

 have alio their leaves divided into wider and 

 , more obtufe fcgments. 

 h A variety of this Lichen fometim.es occurs with 

 ^* leaves tinged of a red or purple colour, called 



by Ray\ Lichencides arhoreim purpurafcens^ tenus 

 ^ Uvefcutellis majoribus. R. Syn. 73. 

 This Lichen is ufed by finches, and other fmall 

 birds, in conftruding the outfide of their cu- 



' riouOy-form'd nefts. . 



G g g L. im." 



