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.
The plants were found on a hard slate that gave no CO2 with HCl, often with Lecidea rhaetica f. dispersa.
Thallus obsolete or very thin, grayish-white or grayish-yellow.
Perithecia minute or very tiny, globose, diam. 0.15-0.25 mm, epilithic, appressed to substrate, numerous, regularly dispersed, black, opaque, not depressed towards ostiole. Amphithecium thick, halved, carbonaceous. Excipulum intact, black. Spores hyaline, simple, large: 21-28 (-30) X (10-) 13-15 µ.
Nucleus J red.
Its minute perithecia and its obsolete thallus suggest Verrucaria acrotella, but its spores are much too large, especially too broad. VAINIO, who has had free access too (sic) ACHARIUS’ type, records 11-21 X 7-9 µ for that species, I measured 10-13 X 5-6 µ in my plant. The amphithecium is not distinctly limited from the excipulum in Verrucaria obsoleta. Unfortunately the perithecia were so firmly attached to their substratum that I did not succeed in detaching a quite intact excipulum. I cannot quite exclude the possibility of a species of the leucobasis section, but what I saw was black.