Pleopsidium flavum (Trevis.) Körb.

Syst. Lich. Germ.: 114, 1855. Basionym: Acarospora flava Trevis. - Rev Per. Lav. Imp. R. Acad. Padova, 1: 262. 1852, non Lichen flavus Bellardi nom. illegit.
Synonyms: Acarospora chlorophana f. dissoluta H. Magn.; Acarospora oxytona (Ach.) A. Massal.; Gussonea flava (Trevis.) Anzi; Gussonea oxytona (Ach.) A. Massal.; Lecanora oxytona Ach.; Pleopsidium oxytonum (Ach.) Rabenh.
Distribution: N - TAA (Hafellner 1993), Lomb (Dalle Vedove & al. 2004), Lomb (Hafellner 2022), Piem (Morisi & Sereno 1995, Allisiardi 2001, Isocrono & al. 2003, 2004, 2006, Morisi 2005), VA (Piervittori & al. 1998, 2001, Piervittori & Isocrono 1999, Isocrono & al. 2008, Matteucci & al. 2015c), Lig. C - Sar (Hafellner 1993, Reeb & al. 2007). S - Cal (Puntillo 1996), Si.
Description: Thallus crustose-placodioid, bright yellow, somehow glossy, epruinose, forming large rosettes, several thalli often merging to cover large surfaces. Central areoles verrucose; marginal lobes well-developed, to 2.3 mm long and c. 0.5(-1) mm broad, slightly convex or flat, branched and incised, the surface often rough. Cortex prosoplectenchymatous, pale yellow throughout, inspersed with crystals, 40-75 µm thick; algal layer continuous or irregularly interrupted; medulla white, intricately prosoplectenchymatous. Apothecia half-immersed in thallus, to 0.8 mm across, with a brownish yellow, concave to flat disc and a thick, smooth to crenulate thalline margin. Exciple dark yellowish, 30-50 µm thick; epithecium greenish yellow, inspersed with yellowish crystals, 15-20 µm high; hymenium colourless or yellowish-striate, (50-)60-80(-100) µm high, IKI+ blue; paraphyses mostly simple, separating easily, c. 2 µm thick, the apical cells not swollen; hypothecium colourless, I+ brown-yellow or pale blue. Asci >100-spored, clavate, with a distinct apical dome reacting I+ deep blue only in the lower outer part, a broad ocular chamber, and an amyloid outer gelatinous sheath, Pleopsidium-type. Ascospores 1-celled, hyaline, narrowly ellipsoid, 4-5 x 1.5-2 µm. Pycnidia immersed, poorly evident, the jelly I+ blue. Conidia ellipsoid, often narrower at one end, 3-5 x 1.5-2 µm. Photobiont chlorococcoid. Spot tests: thallus and apothecia K-, C-, KC-, P-, UV+ orange. Chemistry: rhizocarpic acid plus fatty acids (acaranoic and acarenoic or lichesterinic acids).
Note: on vertical or rain-sheltered surfaces of often metal-rich siliceous rocks in exposed situations, somehow more common than P. chlorophanum in the mountains of Southern Italy, and in areas with a continental climate, as in the xerothermic parts of the Alps.
Growth form: Crustose
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
In underhangs rarely wetted by rain

Commonnes-rarity: (info)

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

pH of the substrata:

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(info)

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

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_P/Text_P/Pleopsidium_flavum.htm
France, session AFL 2007 - Ardèche - 07



Pier Luigi Nimis - CC BY-SA 4.0
TSB 38520



Pier Luigi Nimis CC BY-SA 4.0
TSB 42511


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_P/Text_P/Pleopsidium_flavum.htm
France, session AFL 2007 - Ardèche - 07


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_P/Text_P/Pleopsidium_flavum.htm
France, session AFL 2007 - Ardèche - 07


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_P/Text_P/Pleopsidium_flavum.htm
France, session AFL 2007 - Ardèche - 07



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (10493)
2001/11/28


Bernard Bouffinier - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Corse, Lac de Melo


Bernard Bouffinier - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Corse, Lac de Melo


Bernard Bouffinier - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Corse, Lac de Melo


Bernard Bouffinier - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Corse, Lac de Melo


Bernard Bouffinier - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Corse, Lac de Melo


Alain Gerault - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche, Saint Andreol de Fourchades


Lionel Gerault - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche


Lionel Gerault - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche


Lionel Gerault - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche, Saint Andreol de Fourchades


Lionel Gerault - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche, Saint Andreol de Fourchades


Lionel Gerault - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche, Saint Andreol de Fourchades


Lionel Gerault - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche, Saint Andreol de Fourchades


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Col de Sarenne Oisans


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Col de Sarenne Oisans


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Col de Sarenne Oisans


Bernard Bouffinier - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Corse, Lac de Melo


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche


Jacques Haine - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=1215&lang=en
France, Ardeche


Naira Sargsyan - Institute of Botany A. Takhtajyan, Yerevan CC BY-SA 4.0
Armenia


Naira Sargsyan - Institute of Botany A. Takhtajyan, Yerevan CC BY-SA 4.0
Armenia


Naira Sargsyan - Institute of Botany A. Takhtajyan, Yerevan CC BY-SA 4.0
Armenia