30 BERNT LYNGE. M.-N. Kl. 



undulate or crenato-incise outline, they are plane or in some varieties 

 slightly conv-ex, originally smooth or later on — specially about the centre 

 — more or less rugose, and frequently instructed with numerous short, 

 verrucose or papillose secondary laciniae. Thallus without pruina, 

 isidia or soredia, but suffused with numerous small white 

 dots. Colour white or grey i sh- wh i te, moistened with a faint cast 

 of green, but never apple-green as in Ph. pulvenilenta. 



Upper cortex in the exterior part pale greyish (8 — 16 //), otherwise 

 uncoloured. Hyphae plectenchymatous, rather thick-walled with spacious 

 cell-rooms Gonidia glomerate in a stratum with a very unequal upper 

 surface, its distance from the surface of the thallus varying from 10—45 

 or even 55/*. Medulla white, hyphae loosely woven, especially in the 

 upper part, slightly adsperse, 2,5 — 4,5 h thick. Lower cortex more or 

 less well marked oft" from the medulla, 15 — 60 /< thick, either entirely 

 uncoloured, or in the outer part darker coloured. The majority of the 

 hyphae are more or less parallel to the surface. Sometimes the lower 

 cortex is locally plectenchymatically developed. Rhizinae 50 — 90/« thick. 



Apothecia well developed, sometimes covering the central part of the 

 thallus. They are rounded or angulose, due to mutual pressure. Margin 

 thick, persistent, entire or crenate, but without fololi. Disc plane, opaque 

 or slightly shining, colour reddish brown or black, without or in some 

 varieties with a white pruina. Receptacle more or less rugose, of the 

 same colour as the thallus or yellowish about the centre. Its cortex is 

 very thick, up to 220 //, uncoloured or faintly shadowed in the exterior 

 part, built up of very refractive, 5—6 // thick hyphae, which are perpen- 

 dicular to the surface in the exterior part, and of a more irregular direc- 

 tion in the interior part. Gonidia crowded in and near the margin and 

 arranged in a more or less continuous stratum under the hypothecium 

 and within the cortex, but only scattered in the thin medulla. Hymenium 

 in the outer part yellowish or reddish-brown, otherwise uncoloured, fre- 

 quently with oildrops; 100 — 130 n thick. Paraphyses 2 — 2,5 ." thick, 

 slightly clavately incrassate towards the ends, in the thick part constric- 

 tedly, otherwise indistinctly septate, they are undivided or more or less 

 branched. Asci clavate, 65-70 // long, 14-20 u thick, octosporous. 

 Spores obliquely biseriate or sometimes parallel to the asci, straight, 

 ellipsoidic or slightly flattened on one side, not constricted, rounded 

 at the ends. Cell-rooms connected through a distinct canal; they 

 are small, either angulose and stretched across the .spores or 

 rounded (like a sand-glass); dimensions 20—26 (29I n long, 8,5 — 11 

 (13)« thick. 



