Lynge B 1928. Lichens from Novaya Zemlya. In Holtedahl O. Report of the Scientific Results of the Norwegian Expedition to Novaya Zemlya 1921. Oslo. 1-299.
Thallus small, diam. ca. 10 mm. Areolae minute, diam. 0.2-0.5 mm, plane or slightly convex, rounded or more angular, pale whitish-grey, smooth, almost shiny, margin becoming distinct, dispersed, center becoming more confluent. Hypothallus areolae conspicuously black, plicate-rimose and imposed upon well-radiant thallus margin. Hypothalline zone beyond thalline zone 1.5-2 mm broad.
Apothecia numerous, minute, diam. 0.2-0.45 mm, immersed in areoles, subequal with thallus or margin slightly elevated. Disc black, plane or subconcave, rugose, epruinose, margin thick, at last almost exclusively surrounding disc. Hypothecium pale grayish-brown. Hymenium 65-70 µ tall, paraphyses not coherent, apices thick and olive-greyish-brown. Spores 8, dark, 2-celled, slightly constricted at middle, 13-17 X 8-10 µ; spore membrane moderately thin, unequally thick.
Pycnidia not seen.
Thallus J ÷, CaCl2O2 ÷, KOH temporarily interjected with red (crystals precipitated fasciculately). Hymenium J persistently blue.
Its immersed apothecia refer it to the Melanaspicilia of VAINIO. It differs from all the species described by VAINIO in Lich. Pitlek. by its chemical reaction. It is nearly allied to the two species Buellia sororia TH. FR. Lich. Scand. pag. 603 and Buellia aethalea (Ach.) Th. Fr. l.c. pag. 604. VAINIO, who has been kind enough to study my plant, suggested Buellia aethalea. Is (sic) agrees morphologically quite well with that species, but I have tested its reaction with J over and over again, and always found it negative. That should exclude Buellia aethalea. Its spores are a little larger, especially somewhat broader than in Buellia aethalea: 13-17 X 8-10 against 10-15 X 6-8, but this difference must be within the limits of variation. The different colour is more important. Buellia aethalea is “cinerascens vel fuscidulo-cinerascens” (TH. FR. Lich. Scand. pag. 604) and this agrees with all the plants, which I have seen, e.g. MALME Lich. Suec. No. 12 and ARNOLD No. 1628. ARNOLD No. 1767 is paler, but distinctly brown.
Buellia immersa agrees with Buellia sororia with respect to its reaction, but the brown colour of the latter species should make them distinct.
The genus Buellia is much in want of a monography. It is quite possible that a monography based on a larger material would rearrange several species, but so far I have been unable to find another Buellia so nearly related to this species that I could unite them.