ABEOTHALLUS. 



313 



inconspicuous. Stylospores obovate-globose and very obtuse, 

 pale. 



This species is the var. parasitica of Parmelia saxatilis, 

 according to Schserer ; the Lichen parasiticus of E. B. 1866 ; 

 the Endocarpon parasiticum, Ach. ; and the Lecidea Parme- 

 liarum of Sommerfeldt. We have met with it in consider- 

 able abundance growing on furfnraceous forms or states of 

 Parmelia saxatilis in two stations near Perth, viz. on Craigie 

 Hill, Perth, and on Craig-y-Barns, Dunkeld. In both cases 

 the Parmelia was found on an old wall, built of fragments 

 of rock, or of boulders, belonging to the granitic or me- 

 tamorphic series, especially gneiss. Hooker mentions its 

 occurrence on var. ompltalodes of P. saxatilis, at the foot of 

 Ben Nevis and on the hill-moors of Ross-shire ; and Tulasne 

 on Parmelia quercifolia, var. tiliacea and P. olivacea. In 

 specimens collected and examined by ourselves the plant 

 grows on modified portions of the thallus of P. saxatilis. 

 Sometimes these are simple, minute, and squamose; they 

 then closely resemble the scale-like thalli of some of the 

 Endocarpons, and the similarity is greater if they are dotted 

 over with the point-like pycnides instead of 4he wart-like 

 apothecia; these squamules appear truly separate from, and 

 parasitic upon, the ordinary thallus of the Parmelia saxatilis, 



