Acarospora sulphurata var. rubescens Buschardt

in Leuckert & Buschardt, Nova Hedwigia, 30: 802, 1978.
Synonyms:
Distribution: N - TAA.
Description: Thallus crustose, areolate-placodioid, bright yellow to (rarely) greenish yellow in shade-forms, matt, forming rosettes to 4 cm across. Lobes 0.5-1 mm wide, crenate, plane; central areoles irregular in shape, c. 1 mm wide, contiguous, flat to subconvex, separated by deep fissures. Upper cortex 35-50 µm thick, opaque, with more or less perpendicular hyphae; algal layer continuous; medulla white, 135-170 µm thick, with crystals dissolving in K. Apothecia to 10 per areole, lecanorine, first punctiform and immersed, then slightly expanded, 0.1-0.3 mm across, with a yellowish brown, round to irregular, plane to slightly concave disc and a thin, often indistinct margin. Excipulum indistinct or to 15 µm wide; epithecium yellowish green to yellowish brown; hymenium colourless, 100-120 µm high; paraphyses 2-2.5 µm thick, the apices hardly swollen. Asci >100-spored, clavate, the apical dome conspicuous, K/I-. Ascospores 1-celled, hyaline, globose to subglobose, 2-4(-5.5) x 2-3(-4) µm. Photobiont chlorococcoid. Spot tests: upper cortex K+ yellow turbning red (needle-like crystals), C-, KC-, P- or P+ yellow; medulla K-. Chemistry: upper cortex with rhizocarpic and norstictic acids.
Note: perhaps this is just a chemical strain, hitherto known only from the Alps, which deserves further study.
Growth form: Crustose placodiomorph
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)
Poorly known taxon in need of further study

Commonnes-rarity: (info)

Alpine belt: absent
Subalpine belt: absent
Oromediterranean belt: absent
Montane belt: extremely rare
Submediterranean belt: extremely rare
Padanian area: absent
Humid submediterranean belt: absent
Humid mediterranean belt: absent
Dry mediterranean belt: absent


pH of the substrata:

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Solar irradiation:

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Aridity:

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Eutrophication:

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Poleotolerance:

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Altitudinal distribution:

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