I9l6. No. 8. MONOGRAPH OF THE NORWEGIAN PHYSCIACEAE. 3! 



Pycnides numerous or very numerous, located in the ends of the 

 laciniae, globose or depresso- globose diam. 200 240 //. Perifulcrium black 

 abouth the ostiolum, otherwise uncoloured, or only locally darkened. 

 Basidia 5 6 ti long, 4 5 // thick. Pycnoconidia straight, cylindrical or 

 slightly incrassate at the septum, 4 5 <5,5), long, i i,5, thick. 



React. Cortex as well as medulla distinctly yellow by KOH, 

 no colour by CaCLCX. Hymenium first blue, then black or sordid vinous 

 red by J. 



The statements of the dimensions of the spores vary : CROMBIE 

 1626X811, HARMAND 2428X1013, SANDSTEDE 1624X710, 

 JATTA (Sylloge p. 140) 24 36X6;', which is certainly incorrect. 



Physcia aipolia is on a whole a larger plant than Ph. stellaris, and 

 well separated from this species by the more elongate and plane laciniae, 

 which are more closely appressed to the substratum, and especially by 

 the KOH-reaction of the medulla. The spores are longer, but not thicker, 

 than in Ph. stellaris; large ste//aris-sporcs are so long as medium-sized 

 aipolia spores. 



Physcia concrustans NYL. J has a distinct positive KOH-reaction of the 

 medulla, and cannot, accordingly, belong to the Ph. obscura tribe. It has 

 a thick, very rugose thallus. Prof. ELFVING, Helsingfors, was kind enough 

 to send me a specimen for comparison. 1 consider it to be merely a 

 morbid Ph. aipolia. 



The lichenologists have proposed numerous varieties of Physcia aipolia. 

 It will be seen from the descriptions that the}' differ in characters, which 

 are very variable in the genus. It is hardly possible to attribute a great 

 systematic value to them, with the exception of the angustata, which can 

 safely be raised to the rank of a subspecies, and perhaps to a proper 

 species (petit espece). ACHARIUS, the great founder of our science, arran- 

 ges the varieties into a juvenile one (f. acrita) with a pale lower side, 

 uncoloured rhizinae, and apothecia with entire margin, and into two adult 

 ones I f. ccrcidia with black rhizinae and contiguous laciniae, and f. anthelina 

 with pale lower side and discrete laciniae. 



1 Addenda nova p. 350. 



