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Aspilidea myrinii (Fr.) Hafellner
Family: Incertae Sedis
[Aspicilia cinerea var. myrinii (Fr.) Th. Fr.,  more]
Aspilidea myrinii image
Halfellner, J., Turk R. 2001. Die lichenisierten Pilze Osterreichs--eine Checklist der bisher nachgewiesenen Arten mit Verbreitungsangaben. Stapfia 76:149.

Thallus whitish grey, yellowish grey or ochraceous, rimose to verrucose-areolate, effuse, often forming large patches with a diameter of several dm2; upper surface smooth to rugose, often finely papillate or seemingly granulose; hypothallus sometims visible at margin, concolourus with thallus to greenish black, sometimes fimbriate. Cortex c. 20–40 µm thick, paraplectenchymateous, sometimes covered by a thin epinecral layer, to 9 µ thick.

Apothecia 0.2–1.8 in diam., innate and slightly concave to adnate and flat to slightly convex, sometimes coalescing; pseudothalline margin present, irregularly developed, often replaced by black proper margin, sometimes excluded in convex apothecia; disc black, sometimes pruinose, often with narrow irregular fissures. Subhymenial layers c. 60 µm, hyaline or slightly yellowish. Hymenium to 130 µm tall, hyaline, I+ blue. Epihymenium green-black, N+ green. Paraphyses branched and anastomosing, to 2 µm thick, uppermost cell elongate and not or slightly widened. Proper exciple indistinctly delimited from hymenium and surrounding medullary hyphae, with a c. 30 µm brownish black rim in outer part. Asci apically thickened, indistinctly I+ blue in lower outer part of tholus, 66–84 × 23–29 µm. Ascospores simple, hyaline, 10–20 × 7–11 µm.

Pycnidia globose to ellipsoid or pyriform, c. 20–25 µm in diam., wall with green-black pigment in upper part. Conidia bacilliform, 4.5–8 × 1 µm. Conidiogenous cells c. 8 × 2 µm, attached singly or two or three together to simple or slightly branched conidiophores.

Chemistry. Thallus K + yellow turning red, C –, PD + orange; containing norstictic and connorstictic acids.

Notes. Aspilidea myrinii is similar to the common and widespread Aspicilia cinerea but can be distinguished in the field by the often yellowish, large thalli and the less urceolate apothecia with a more irregular margin and an often rimose disc. Under the microscope the euamyloid hymenium, the non-moniliform paraphyses and the short conidia are distinctive. It often hosts the lichenicolous fungus Sagedia fissurisedens, so far only found growing on the thallus of Aspilidea myrinii.

Habitat and distribution. Aspilidea myrinii grows in open situations on crystalline schists and siliceous rocks. In Fennoscandia the species is almost entirely restricted to the alpine zone of the Scandinavian Mountains, but may also be found at lower altitudes, particularly close to the coast in northern Norway. Outside Fennoscandia it is known from similar habitats in mountainous areas of Europe, Asia and America.