456 40. LECANORA SAXICOLA. [CL. XXIV. 



3. 396. Engl Bot. S232. Weh. Proclr. Hepat. p. 42. 



Mart. FL Crypt Erlang p. 141. t. S. f. 14. 

 J. radicans, Hofm. Germ. % 87. 

 J. stolonifera, Sw. Fl. Ind. Occid. 3. 1862. 



Geographical Distribution, 



This plant is dispersed throughout the temperate zone of 

 the whole northern hemisphere. It is found in the south of 

 Sweden, in Norway, and Scotland, as well as in France, 

 Italy, and Germany. I have also received it from New 

 York. As J. stolonifera Swartz, and J. tricre7iata Bridol, 

 brought by Bory S. Vincent, are the same with this plant, 

 it grows also between the tropics, at least in Jamaica, and 

 Mascaren's Island, 



V. Lichens. 

 40. 



Lccanora saxicola, Ach. 



This lichen grows abundantly on field-stones, on porphyry 

 and sandstone rocks. Its thallus is thick accumbent, scaly, 

 wrinkled, dissimilar, often as it were broken, and of a dirty 

 palegreen, or yellowish-green colour, whitish, and smooth be- 

 neathj but formed into radiated lobes on the margin. The 

 whole lichen has often a diameter of several inches, and in 

 its perfect state, on level stones, it is circular. The pale gem- 

 miferous dust exudes in spring, on the surface. The appa- 

 rent fruit is flat, round, without stalks, and pressed together, 

 of a dirty, reddish-yellow colour, surrounded by a pale mar- 

 gin resembling a thallus, and of the size of lentil or mustard 

 seed. It stands in closely crowded heaps, commonly in the 

 centre of the thallus, is frequently irregular, without the 

 margin resembling a thallus, and contains opake grains iii 

 fine tubes. 



