CL. XXIV.] iO. LKCANORA SAXICOLA. 457 



Diagnosis and Affinity. 



This species has a great resemblance to Lccanora slra- 

 minca Ach., (Tab. II. Fig. 3). But, in this last named 

 species, the thallus is straw-coloured. The lobes are quite 

 linear on the margin, roundish when cut through : the cen- 

 tral lobes are also as it were inflated. The colour of the ap- 

 parent fruit is darker, and the margin, which resembles a 

 thallus, is as it were swollen. Lcc. versicolor Ach. also re- 

 sembles it : but this species grows almost exclusively on cal- 

 careous rocks. The thallus is whitish on the margin, of a 

 a dirty-green in the centre. The apparent fruit, when young, 

 is of a flesh colour, and has a white margin : afterwards it 

 is of a dark dirty red, and the margin vanishes. Lee. crassa 

 Ach. corresponds, indeed, in the colour of the thallus, and of 

 the apparent fruit ; but the structure is quite different, for 

 it consists of single, cartilaginous, crenated, undulated, bent 

 lobes, which lie like scales on one another : the lower surface, 

 koo, is brown, and the apparent fruit stands dispersed. 



Synonymes and Figures. 



? Lichen pulmonarius saxatilis farinaceus glauco-virescens, 



Michel. Nov. Gen. p. ^4<. t. 51. f. 4. 

 Lichen saxicola, Pollieh. Palat* n. 1098. Engl. Bot. 1695. 



Achar. Lichenogr. Suec. Prodr. p. lOi. WaJdenh. Fl. 



Lappon. p. 415. 

 L. murahs, Schreb. Spec. Fl. Genn. p. 130. Wither. Arrang. 



4. 31. 

 L. ochroleucus, Wulff. in Jacqu. Coll. 2. t. 13. f. 4. a. 

 Tsora muralis, Hqfm. PL Lichen, t. 16. f. 1. (male.) 

 Parmelia saxicola, Ach. Method, p. 191- Mart. Fl. Crypt. 



Erlang. p. 215. 

 Lccanora saxicola, Ach. Lichenogr. p. 431. Syn. j). 180. 



Geographical Disirihuiion. 



Although this lichen i;> dispersed through Kuropc, from 

 Lapland to Italy, and from the Pyrenees to Tauiis, no traces 

 pf it are to be found in more distant countries. 



