Magnusson, AH. 1939. Studies on Species of Lecanora, Mainly the Aspicilia gibbosa Group. Kongl. Svenska Vetenskapsakad. Handl. 17: 34-35.
Thallus thin, sordid chalky white and +/- farinose, only partly continuous at the centre, partly evanescent, lobate at the circumference with almost squamuliform, about 0.2 mm broad, indistinctly limited lobes, KOH-, no distinct hypothallus.—Cortex 40-60 µ thick, white from granules like the medulla, transparent in HCl, amorphous stratum with indistinct surface, hardly darker. Hyphae in HCI intricate, +/- lax, cells about 2 µ thick-walled. Gonidia 8-15 µ stratum 35-50 µ +/- continuous. Medulla in HCl with perpendicularly intricated, thick-walled, lax hyphae, lumina about 2 µ.
Young fertile areolae about 0.5 mm wide with solitary apothecia, older central ones 1-1.5 mm wide, 0.4-0.5 mm thick, with 3-6 apothecia, De 60-100, disc depressed, concave, black, partly pruinose, 0.2-0.3 mm broad, surrounded by a prominent, blackish, whitish-pruinose, thick margin, where the dark colour gradually passes into the white thallus colour on the outer side.—Exciple distinct, between two apothecia 50 µ thick, +/- dark borwnish, at the base and laterally pale, 18-35 µ thick, I-, upper surface not stained in KOH. Hypothecium 40-50 µ, yellowish opaque. Hymenium 100-120 (135) µ high, I+ blusih-green to brownish-yellow; upper 12-17 µ yellowish-olive. Paraphyses 1.5-1.7 µ in water, contiguous, non-guttulate, in KOH non-moniliform, much branched, apices hardly thicker, about 2 µ, whole paraphyses +/- constrictedly septate. Asci about 100 X 35 µ, swollen clavate. Spores 8, broadly ellipsoid, 17 X 12 µ, or +/- globose, about 13 µ, acc. to HUE 20-24 X 14-18 µ or sphaeroid 14-20 µ.
Habitat. On calcareous rock.
Distribution. Spitsbergen. Treurenberg Bay, MALMGREN (O.) called L. gibbosa v. squamata by TH. FRIES. Spitsbergen 1890 (hb. HUE, Paris) type.—Norway. Tromsö: Flöjfjeldet 1864 TH. FRIES (U.) called L. bicolor H. MAGN. In Förteckn. Skand. växter, 4. Lavar (1936) 57 (nomen nudum).—Novaya Zemlya. North of Mashigin mouth 1921 LYNGE (O.) called L. Lyngei by ZAHLBRUCKNER.
L. virginea resembles L. alboradiata, Lesleyana, disserpens and above all candida in the white colour and the +/- distinct lobes at the circumference. Only when, through the kindness of prof. ALLORGE, Paris, I got the opportunity of examining HUE’s authentic specimen, I could persuade myself of its specific rank. It is separated from disserpens by its broader indistinct lobes, the broader spores and much thicker cortex, from alboradiata by the lobes, the broader spores and much thicker cortex, from alboradiata by the prominent, dark apothecial margin and thicker cortex, from Leselyana and candida by the lacking K-reaction in the upper part of the exciple (and epithecium), from the former by the higher hymenium and broader spores. The difference towards candida and especially its variety nikrapensis lies mainly in the lacking K-reaction of the exciple because candida seems to be a variable species both as to the height of its hymenium, the size of its spores and the thickness of its cortex. It is also to be supposed that the development of the thallus in the Arctic is liable to considerable reduction when compared with the fully developed specimens from the Alps. Yet, it is possible that L. virginea is only a reduced form of candida.