Squamarina gypsacea (Sm.) Poelt

Mitt. bot. Staatss. München, 2: 539, 1958. Basionym: Lichen gypsaceus Sm. - Trans. Linn. Soc. London, 1: 81, 1791.
Synonyms: Lecanora crassa var. gypsacea (Sm.) Rabenh.; Lecanora fragilis Zahlbr.; Lecanora gypsacea (Sm.) Müll. Arg.; Lecanora smithii (Ach.) Ach.; Placodium gypsaceum (Sm.) Trevis.; Psoroma gypsaceum (Sm.) A. Massal.; Squamaria gypsacea (Sm.) Nyl.
Distribution: N - VG, Frl, Ven, TAA, Lomb, Piem, Emil (Tretiach & al. 2008, Fariselli & al. 2020), Lig. C - Tosc (Benesperi 2006, Benesperi & Lastrucci 2007, Lastrucci & al. 2009, Brackel 2015), Marc, Umb (Genovesi & Ravera 2001, Ravera & al. 2006), Laz (Nimis & Tretiach 2004), Abr (Gheza & al. 2021), Mol (Nimis & Tretiach 1999, Caporale & al. 2008, Genovesi & Ravera 2014), Sar. S - Camp (Aprile & al. 2003b, Nimis & Tretiach 2004, Garofalo & al. 2010), Pugl (Nimis & Tretiach 1999), Bas (Nimis & Tretiach 1999), Cal (Puntillo 1996), Si (Nimis & al. 1994, 1996b, Ottonello & al. 1994, 2011, Ottonello 1996, Ottonello & Romano 1997, Grillo 1998, Grillo & Caniglia 2004).
Description: Thallus squamulose, rather firmly attached, consisting of usually dispersed, more or less isodiametrical to slightly elongate, concave, to 8 mm broad and to 3-5 mm thick squamules, the upper surface green, the margins conspicuously white. Lower surface white at margins, dark in central parts. Upper cortex inspersed with pale brown granules dissolving in K, overlain by a thin epinecral layer; medulla white, thick, filled with calcium oxalate crystals; lower cortex absent Apothecia rather rare, lecanorine, sessile, with a flat to slightly convex, 1-1.5 mm broad, sometimes slightly white pruinose, pale brown disc and a thin, often finally disappearing thalline margin. Cortex of thalline exciple similar to that of the thallus; proper exciple reduced to a thin ring; epithecium brown with pale brown granules dissolving in K and calcium oxalate crystals; hymenium colourless, inspersed with granules dissolving in K, I+ blue; paraphyses mostly simple, c. 2 μm thick; hypothecium with pale brown granules dissolving in K, not subtended by an algal layer. Asci 8-spored, narrowly clavate, the wall I+ blue, with a I+ blue apical dome, without axial mass, Bacidia-type. Ascospores 1-celled, hyaline, narrowly ellipsoid with rounded ends, 10-15 x 4-7 μm. Photobiont chlorococcoid. Spot tests: cortex K-, C-, KC- or KC+ yellowish, P , UV-; medulla P+ yellow. Chemistry: cortex with usnic and isousnic acid, medulla with psoromic acid.
Note: in fissures of calcareous boulders, sometimes also directly on rock, with optimum in the Mediterranean-submediterranean belts, often growing on the thalli of Romjularia lurida. Most records from above treeline refer to S. subcetrarioides.
Growth form: Squamulose
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)
paras Romjularia lurida

Commonnes-rarity: (info)

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

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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Predictive model
Herbarium samples

Leif Stridvall - Source: http://www.stridvall.se/la/galleries.php (Courtesy: Anita Stridvall)



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (31676)
2001/12/11



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (31676)
2001/12/11
apothecium



Pier Luigi Nimis CC BY-SA 4.0
TSB 41732


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_S/Squamarina_gypsacea.htm
France, fisures de rochers - session AFL 2010 - Hérault - 34)


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_S/Squamarina_gypsacea.htm
France, fisures de rochers - session AFL 2010 - Hérault - 34)