CL. XXIV.] 40. LECANORA SAXICOLA. 



457 



Diagnosis and Affinity. 



This species has a great resemblance to Lecanora stra^ 

 minea 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. Lec, 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. Lec. 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^ 

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



Syncmymes and Figures. 



P Lichen pulmonarius saxatilis farinaceus glauco-viresccns, 



Michel Nov. Gen. p. 34. t. 51. f 4. 

 Lichen saxicola, Pollicli. Palat. n. 1098. Engl. Bot. 1695. 



Achar. Lichenogr. Suec. Prodr. p. 104. Wahlenh. Fl. 



Lappon. p. 415. 

 L. muralis, Sclireb. Spec. FL Germ. p. 130. Wither. Arrang. 



4. 31. 



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

 Psora muralis, Hofm. PL Lichen, t. 16. f. 1. (male.) 

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



Frlang. p. 215. 

 Lecanora saxicola, Ach. Lichenogr. p. 431. Syn. p. 180. 



Geographical Distributio7i. 



Although this lichen is dispersed through Europe, from 

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

 of it are to be found in more distant countries. 



