314 



POPULAR HISTORY OF LICHENS. 



but, like it, they are black-fibrillose below, and otherwise 

 possess characters which justify our regarding them as be- 

 longing to that Lichen, and not to the parasitic Abrotliallus, 

 which is hence athalline. More usually however these por- 

 tions of the thallus of the Parmelia are much deformed, ap- 

 parently from a peculiar curling in of the laciniae, and as- 

 sume the character of irregularly globose, gnarled masses, 

 dotted over with the black or greenish pulverulent apothecia 

 of the Abrotliallus. In the latter case we have frequently 

 noticed them of a deep rusty-red colour, apparently from the 

 imbibition of peroxide of iron from the stones or soil. This 

 species of coloration, we have already seen, is somewhat com- 

 mon in alpine and subalpine saxicolous Lichens. The laci- 

 nise of P. saxatilis, modified or deformed by the growth of 

 the parasite, have been described by De Notaris as the pro- 

 per thallus of the genus Abrotliallus ; hence the inappro- 

 priate name originally conferred on it by him. The pyc- 

 nides of this species probably have not escaped the notice 

 of previous Lichenographers. Fries appears to refer to 

 them when he speaks of " puncta verrucarioidea nigra" of 

 Parmelia saxatilis, which he regards as a less fully deve- 

 loped or younger state of the cephalodia of the same Lichen, 

 the latter being the apothecia of Abrotliallus Smithii, as 



