196 



POPULAR HISTORY OP LICHENS. 



and their spermatia straight. This species is found in the 

 Antarctic regions, in North America, Australia, and other 

 foreign countries. 



8. Parmelia ceratophylla (/cepas, a horn). Thallus 

 membranaceous, whitish -glaucous, below pitch-coloured, 

 smooth ; lacinise sinuate-multifid, somewhat convex or 

 rounded ; at their extremities inflated, imperforate, fringed 

 or tipped with pale soredia. Apothecia reddish-brown, some- 

 times subpedicellate and cup-shaped, becoming explanate, 

 margin entire. This species varies greatly in the discreteness, 

 size, and mode of division of the lacinise, and in the ascend- 

 ing or inflexed, inflated and sorediiferous characters of their 

 extremities ; the lacinise are frequently, especially towards 

 their extremities, black -punctate, or as if pricked over with 

 a thick series of black points, to such an extent that one 

 variety is denominated multipuncta. 



One of our commonest British Lichens, growing abun- 

 dantly on trees, rocks, and walls, almost everywhere. In 

 the vicinity of Perth it is exceedingly common on the 

 branches and stems of the fir, and on heather and other 

 shrubs in the hill-woods ; on boulders, especially granitoid, 

 which are plentifully scattered over the face of the country ; 

 and on every roadside wall. It is also frequent in High- 



