Geographical Societyøya: Husbukta, on a basaltic rock (no CO2 by HCl). Thallus of moderate width in specimen fragment, c. 4-5 cm. Hypothallus thin, ochraceous, rimose throughout and causing it to be minutely subareolate. Upper hypothallus thalline verrucae revolute, deeply verrucose, constricted base, flexible, rounded, diam. to 0.5-0.7 mm, smooth or very slightly rimulose or still subcariose (X 64), white, maculate above or maculae rounded, ornate. Central verrucae dispersed or subdispersed, peripheral to more confluent, indistinctly radiate, the crust of areolate-verrucose form. Hypothallus margin ashy-yellow, indistinctly developed or revolute, spreading throughout and disappearing.
Apothecia sparse, raised well above the thallus, lecanorine, expanded, simple, rounded, somewhat large, diam. to 1.1 mm. Disc black, slightly pruinose, from initially concave and surrounded by thick, white thalline margin, then subplane and completely surrounded by thin, dark gray, proper margin. Apothecia circ. 225 μm tall, exciple indistinctly limited. Hymenium tall, 100-125 μm, pale green above and occasionally with oxalate crystals. Even in water, paraphyses subdistinct, at least in the interior, in HCl + I, septate-constricted, but not moniliform, in HCl + KOH, tumescent and moniliform, furcated on both sides. Spores well developed, ellipsoid, 17-21 μm long.
Pycnidia sought in vain.
Hyphae granules strongly scattered, yet thallus not opaque. Gonidia coalesced and thallus undulate above, for this reason cortex height variable, but thick, 50-75 μm. Cortical hyphae corpuscular, minute, strongly scattered (in water) and indistinct in HCl, yet distinct in KOH, septate-constricted, articulate, leptodermatous, 5-6 μm thick. Yet, medulla pellucid in HCl and KOH.
Magnusson divided the Aspiciliae in two sections, the Effusae and the Orbiculares. It is hardly possible to find a better morphological subdivision. But yet some species are more or less intermediate, and the present one is one of them. There are no radiating lobes, but towards the circumference the thalline verrucae are arranged in a more or less radiating manner.
If placed with the Orbiculares, the white verrucae and the yellow reaction of the surface of the excipulum approach it to Lecanora candida. But it is clearly distinct from that species, it is not cretaceous, its thallus is verrucose, and its apothecia are large, raised and expanded (whence its name). Lecanora candida is restricted to calcareous rocks.
When I first examined the plant (there is but one specimen), KOH precipitated some of the uncoloured, prismatic crystals, seen in several Aspiciliae, but on the final revision I obtained no such precipitation.