70 BERNT LYNGE. M.-N. Kl. 



varying from short and scattered to very numerous and conspicuous, 

 radiating like a corona, and very rarely failing. Cortex 25 50 /< thick, 

 formed of thick-walled, constrictedly septate hyphae, perpendicular to 

 the surface. Gonidia crowded in irregular clusters within the margin of 

 the receptacle, scattered in the medulla and under the hypothecium, few 

 or absent within the black part of the cortex. Hypothecium formed of 

 thick-walled plectenchymatous hyphae, uncoloured, up to 55 , thick. 

 Disc brownish or black, moistened persistently brownish black, plane or 

 slightly convex, epruinose. Hymenium covered with an amorphous un- 

 coloured stratum; 80 no f.t thick, at the exterior part yellowish-brown 

 to dark brown, otherwise uncoloured, not insperse. Paraphyses at their 

 tips clavately incrassate and distinctly constrictedly septate, unbranched or 

 with a few short lateral branches near their apices. Asci 60 75 /< long, 

 1626 u thick, octosporous. Spores obliquely biseriate, straight, ellipsoid, 

 not constricted at the septum, but occasionally flattened on one 

 side, the radius of one contour being shorter than that of the opposite. 

 Colour greyish-brown, old spores almost opaque. Cell rooms angular, 

 stretched across the spore or sometimes resembling a sand-glass. Sep- 

 tum thick. Spores at least twice as long as thick, size 20 25 /< 

 long, 9,312 f.t thick. 



Pycnides numerous, especially towards the apices of the laciniae, glo- 

 bose or with a slightly protrudent ostiolum. Perifulcrium dark around the 

 ostiolum, otherwise uncoloured. Pycnoconidia straight, elliptical, small : 

 2 3 f.i long, i 1,5 /< thick. 



React. Neither cortex nor medulla coloured by KOH or CaCl 2 O^. 

 Hymenium blue, then at once vinous-red or brownish-red by J. 



Hab. On the bark of deciduous trees, especially on Populus tremula, 

 very rarely on Betula. Norwegian saxicolous specimens not recorded. 



Loc. Frequent or even abundant in Southern Norway, recorded as 

 far north as Skoganvarre in Finmarken, but it is rare in Northern Norway. 

 It is most frequent in the lowlands, but it ascends as high as Populus 

 tremula (as a tree), in Eastern Norway to about 800 m., in Western Nor- 

 way to 400 500, rarely to 600 m. above the sea level. On the whole, 

 Physcia obscura has about the same distribution in Norway as Populus 

 tremula 



Abundant near Kristiania from numerous stations in Aker (MoE), 

 Baerum and Asker (LYNGE), abundant in the south-eastern lowlands: Aar- 

 nes (HocH), Rena (KLER), Minne (LYNGE), Veldre (NORDHAGKN), Lillehammer 

 OEBE), Vaage (NORMAN), Dovre(ZETTERSTEDT), Norderhov (NORMAN), Brandbu 



