Lecanora margacea Poelt

in Poelt & Buschardt, Norw. J. Bot., 25, 2: 128, 1978.
Synonyms:
Distribution:
Description: Thallus crustose to subsquamulose, episubstratic, chalky white, thick, forming several cm wide patches, the areoles/squamules 1-3(4-) mm wide, dispersed to contiguous, at first round, then crenulate to lobulate, finely farinose, smooth to rough, the marginal ones often elongate, but not forming placodioid rosettes. Apothecia lecanorine, round to finally irregular in outline, 0.7-1.5(-2) mm across, finally strongly constricted at base, with a concave to flat, medium brown, initially sometimes faintly pruinose, then epruinose disc and a conspicuously thick, raised, often wavy-crenulate to radially split thalline margin. Cortex c. 25 µm thick, poorly differentiated, of conglutinated hyphae, densely inspersed with both small yellowish and larger colourless crystals; algal layer 60-80 µm thick; medulla thick, filled with grey granules. Thalline exciple with a 30-40 µm thick cortex filled by granules, the medullary part rich in algae; proper exciple thin, poorly differentiated, of conglutinated hyphae; epithecium brown; hymenium colourless, 40-50(-60) µm high; paraphyses 1-1.5 µm thick at mid-level, the apical cells capitate, with brownish walls; subhymenium mostly consisting of anticlinally arranged hyphae, and hence scarcely differentiated from the hymenium; hypothecium colourless, of strongly coherent hyphae. Asci 8-spored, clavate, very thin-walled, with a K/I+ blue, tall tholus penetrated by a faintly amyloid apical cushion, the wall K/I-, surrounded by a blue outer layer, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid, 9.5-16 x 5.5-7 µm. Photobiont chlorococcoid. Spot tests: K- or K+ faintly yellow, C-, KC+ faintly yellow, P- or (especially the apothecial margin) P+ yellow. Chemistry: usnic acid, sometimes with additional psoromic acid.
Note: a characteristic species described from Norway and also known from a few localities in the Alps (Switzerland, Austria) and the Balkan Peninsula, growing on calciferous schists and siliceous limestone (Kieselkalk), usually in rather dry upland areas; I have also seen a specimen from Armenia. To be looked for in Italy, both in the Alps and along the Apennines. For further details see Poelt & Buschardt (1978).
Growth form: Crustose
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)

pH of the substrata:

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Predictive model

Einar Timdal - Source: http://nhm2.uio.no/lav/web/index.html - CC BY-NC


Detail from: https://gzu.jacq.org/GZU000290857
GZU000290857 - Poelt,J. & Buschardt,A. Location Norway / Oppland Label Norwegen, Oppland: Trockene, von Kalkschieferfelsen durchsetzte Hänge nordlich des Hofes Viste westlich Vagamo, Gem. Vaga Habitat Trockene, von Kalkschieferfelsen durchsetzte Hänge


Detail from: https://gzu.jacq.org/GZU000290857
GZU000290857 - Poelt,J. & Buschardt,A. Location Norway / Oppland Label Norwegen, Oppland: Trockene, von Kalkschieferfelsen durchsetzte Hänge nordlich des Hofes Viste westlich Vagamo, Gem. Vaga Habitat Trockene, von Kalkschieferfelsen durchsetzte Hänge


Detail from: https://gzu.jacq.org/GZU000290857
GZU000290857 - Poelt,J. & Buschardt,A. Location Norway / Oppland Label Norwegen, Oppland: Trockene, von Kalkschieferfelsen durchsetzte Hänge nordlich des Hofes Viste westlich Vagamo, Gem. Vaga Habitat Trockene, von Kalkschieferfelsen durchsetzte Hänge


Detail from: https://gzu.jacq.org/GZU000290860
GZU000290860 - Collector Schröppel,A. s.n. Date 1953-08-21 Location Austria / Tirol Label Gatschkopf bei Pians im Inntal bei Landeck über der Augsburgerhütte ; Alt. 2400 m


Detail from: https://gzu.jacq.org/GZU000290858
GZU000290858 - Collector J. Poelt - Date 1971-06-01 Location Macedonia Label Jugoslawien, Makedonien: Sar Planina, oberhalb Tetovo, Hänge der Popova Sapka um und oberhalb der Bergbahnstation, Kieselkal, Steilflächen. ; Alt. 1700 m - 2000 m Habitat Kieselkal, Steilflächen.


Detail from: https://gzu.jacq.org/GZU000290857
GZU000290857 - Collector Poelt,J. & Buschardt,A.Date 1976-09-05 Location Norway / Oppland Label Norwegen, Oppland: Trockene, von Kalkschieferfelsen durchsetzte Hänge nordlich des Hofes Viste westlich Vagamo, Gem. Vaga Habitat Trockene, von Kalkschieferfelsen durchsetzte Hänge


Detail from: https://gzu.jacq.org/GZU000290857
GZU000290857 - Collector Poelt,J. & Buschardt,A.Date 1976-09-05 Location Norway / Oppland Label Norwegen, Oppland: Trockene, von Kalkschieferfelsen durchsetzte Hänge nordlich des Hofes Viste westlich Vagamo, Gem. Vaga Habitat Trockene, von Kalkschieferfelsen durchsetzte Hänge


Detail from: https://gzu.jacq.org/GZU000290858
GZU000290858 - Collector Poelt,J. Date 1971-06-01 Location Macedonia Label Jugoslawien, Makedonien: Sar Planina, oberhalb Tetovo, Hänge der Popova Sapka um und oberhalb der Bergbahnstation, Kieselkal, Steilflächen. ; Alt. 1700 m - 2000 m Habitat Kieselkal, Steilflächen.