90 BERNT LYNGE. M.-N. Kl. 



gular, interrupted stratum with varying distance from the surface. Usually 

 the dark upper part of the cortex is thicker above more protruding goni- 

 dia clusters (protection). Lower cortex 30 40 (.1 thick, usually well marked 

 off from the medulla; its exterior part is dark, brown or black; otherwise 

 it is colourless. The majority of its hyphae are more or less parallel to 

 the surface, but many of them have another direction, even perpendicular 

 to the surface. Rhizinae 90 105 /< thick. 



Apothecia are not rare, though the thallus is usually sterile. They 

 are small, rounded with diam. 0,5 i mm., scattered or sometimes crowded 

 in the central part of the thallus; they are closely appressed with persi- 

 stent, originally entire, later on crenate margin, and plane, brownish or 

 black, more or less albo-pruinose disc. Receptacle rugose, pale yellow, its 

 cortex uncoloured or at the exterior part faintly shadowed, o i6o/t thick, 

 hyphae plechtenchymatous, at least at the exterior part perpendicular to the 

 surface. The gonidia fill up the medulla of the margin; they are also 

 numerous within the whole cortex, under the hypothecium and more 

 frequent in the medulla than usually in the genus. Hymenium reddish- 

 brown and very insperse at the upper part (epithecium), otherwise un- 

 coloured, 6580 (100) (.1 thick. Paraphyses at their ends cla- 

 vately incrassate, constric tedly septate, undivided or frequently 

 dichotomously branched. Asci octosporous, cla- 

 vate, rather narrow, 6080^ long, 15 17 /i /Qj 

 thick. Spores often poorly developed, straight, \OJ 

 ellipsoidical or slightly fabaceous, a little con- 

 stricted at the septum, rounded at the ends. 

 Cell room small, angulose, stretched across the 



j j a ( \ Fig. 1 1. Physcia caesia 



spore, or sometimes rounded. Spores (13) / 



1622 |i( long, (7) 7,79,5 (TO) jti thick 



Pycnides very numerous, globose, diam. 130160 /<; perifulcrium 

 almost uncoloured; pycnoconidia cylindrical or slightly incrassate at the 

 middle, 3 4 ( long. The pycnides are quickly emptied, senile pycnides 

 are depresso-globose with black perifulcrium and prominent ostiolum. 



React. Cortex as well as medulla yellow by KOH, not 

 coloured by CaClaCX. Hymenium first blue, then at once dark blue or 

 black, or sometimes sordid vinous by J. 



Physcia caesia has an extensive horizontal as well as vertical distri- 

 bution in our country. It is frequent through the whole country and 

 ascends from the shore at least to 1400 1500 m. in Central Norway 

 (Finse), at least on chalky and schistose substratum. It is also found though 



