I9l6. No. 8. MONOGRAPH OF THE NORWEGIAN PHYSCIACEAE. 63 



Thallus covered with an amorphous colourless stratum of varying 

 thickness. Upper cortex from o (soredia) to 50 or even 75/1 thick; at 

 the exterior part it is more or less dark, otherwise uncoloured. Hyphae 

 spreading like a fan from between the glomerate gonidia, more or less 

 closely interlaced and sometimes almost plectenchymatous; they are 

 3 5 u thick, branched, hardly constricted at the distinct septa. Medulla 

 white or sometimes very faintly yellow, with loosely interlaced horizontal 

 hyphae, more or less distinctly marked out from the lower cortex, which 

 also consists of horizontal but more pachydermatous hyphae. The lower 

 cortex uncoloured in young laciniae, in old laciniae its exterior 

 part is at least at the centre locally or extensively coloured dark, dark- 

 brown or even black. Lower cortex 25 50 u thick, rhizinae branched, 

 diam. up to 130/4. 



Apothecia rare, sessile, but not appressed, diam. up to 3 mm. Margin 

 crenate or even appendiculate, sometimes sorediate, disc pruinose. In some 

 apothecia the gonidia are very numerous, crowded, filling up the whole 

 medulla of the receptacle. Spores frequently with oil drops, 26 34,5 u 

 long, 14,4 18,5 , thick. 



The form of the spores as well as the other carpological characters 

 as in Ph. pulverulenta var. allochroa. 



React. The yellowish soredia and medulla are coloured more di- 

 stinctly yellow by KOH. Otherwise cortex as well as white soredia and 

 medulla are neither coloured by KOH nor by CaCl 2 O 2 . Hymenium first 

 blue, then at once deep vinous by J. 



Ph. grisea includes plants of a very considerable variation. I have 

 tried to describe the varieties in the following manner. 



f. alphiphom (Acn.) LYNGE comb. nov. 



Parmelia farrea f. alphiphora ACHARIUS Lich. Univ. (1810) p. 476. 

 Physcia ** farrea f. alphiphora WAINIO Adjumenta I (1881) p. 132. 

 HARMAND Lich. France (1909) p. 640. 



Ex sic. CLAUD, et HARM. Lich. Gall. 495. 



Laciniae appressed, contiguous or subdiscrete, narrow, equally 

 broad or slightly widened at the ends, multifid, pinnately or dichotomously 

 branched. Peripherical laciniae sorediate along their sides only and there- 



