igi6. No. 8. MONOGRAPH OF THE NORWEGIAN PHYSCIACEAE. 95 



React. Thallus extus et intus KOH flavescens, CaCUOo non muta- 

 tur. Hymenium J caeruleum, dein persistenter caeruleo-nigrescens vel 

 niçrescens. 



f. con vexa n. f. 

 Tab. I, fig. 2. 



Major et robustior, laciniae convexae, latiores, minus diver- 

 genter ramosae et subcontiguae. Soredia thallo concoloria vel in colorem 

 caesiam vergentia, vulgo sparsa, subsidiiformia, granulosa, sat sparsa vel 

 rarius numerosa, globosa, pulverulenta. (Soredia vera, soralia). Thallus 

 maculis albis plus minusve perspicuis instructus. 



f. plana n. f. 

 Tab. I, fig. 3. 



Minor, gracilior, laciniae planae, angustae, elongatae, diver- 

 genter ramosae et eam ob causam discretae. Soredia (vera) parva, alba, 

 depresso-globosa. Thallus maculis albis perspicuis dense instructus. Rhi- 

 zinae inter lacinias distinctae. 



Ad rupes perpendiculares subalpinas et alpinas soli et vento valde 

 expositas, crescens, socio Caloplacac elegantis. 



{. couvexa is frequent along the Kristiania — Bergen railway from Hoi 

 to Finse, 550 — i45om.s.m. (Ly.nge), also known from Dovre (herb. Kiær), 

 and from Skoganvarre in Finmarken (Lynge). 



f. plana is only known from Arctic Norway : Skibotn in Tromsø amt, 

 and Skoganvarre in Finmarken (Lynge). 



Not. It is evident from the description that there is no great difference 

 between the two formae, which most probably only represent individual 

 variation. The affinity of the subsp. ventosa is with Fli. cacsia, it is separated 

 from this species by its colour, more discrete laciniae, lesf coherent and 

 less incrassate paraphyses, and by broader spores. It has another distri- 

 bution : Physcia caesia is a lowland species which only rarely surpasses 

 the forest limit (900 m. in Central Norway), our subspecies is markedly 

 subalpine and alpine. — The apothecia are very rare, and usually sterile. 



