Collema subnigrescens Degel.

Symb. Bot. Upsal., 13, 2: 413, 1954.
Synonyms: Collema vespertilio auct. p.p.; Lathagrium nigrescens sensu A. Massal. (1853); Parmelia nigrescens var. caesia Clemente
Distribution: N - VG, Frl, Ven, Piem, Emil, Lig. C - Tosc (Loppi & al. 1994, 1995, 1997, Frati & al. 2006b, Benesperi & al. 2007, Brunialti & Frati 2010, Paoli & al. 2012), Marc (Frati & al. 2004, Frati & Brunialti 2006), Umb (Ravera 1998, Ravera & al. 2006), Laz (Massari & Ravera 2002, Nimis & Tretiach 2004, Ruisi & al. 2005, Ravera & Genovesi 2008), Abr (Recchia & al. 1993, Nimis & Tretiach 1999, Corona & al. 2016, Gheza & al. 2021), Mol (Frati & al. 2004, Caporale & al. 2008, Paoli & al. 2015, Caporale & Ravera 2020), Sar (Zedda 1995, 2002, Rizzi & al. 2011). S - Camp (Nimis & Tretiach 2004, Nascimbene & al. 2010b, Brunialti & al. 2013, Ravera & Brunialti 2013), Bas (Potenza & al. 2014), Cal (Puntillo 1995, 1996, Puntillo & Puntillo 2004), Si (Nimis & al. 1996b, Grillo 1998, Grillo & Caniglia 2004, 2006, Grillo & Cataldo 2008, 2008b).
Description: Thallus foliose, homoiomerous, subgelatinous when wet, membrane-like, rounded, closely adnate, broadly lobed, 2-7(-15) cm wide. Lobes 0.5-1.5 cm wide, 60-100 µm thick when moist, rounded at apex, with an entire, not swollen margin, dark olive-green to black, lighter and semi-translucent when moist, strongly radiately ridged and postulate, never isidiate. Lower surface paler green than upper surface, at times bluish green, with depressions corresponding to ridges, and scattered white hapters. Upper and lower cortices absent. Apothecia common, lecanorine, sessile and constricted at base, 0.8-1.5(-2) mm across, with an initially concave, finally convex, red-brown to almost black disc and a persistent, smooth thalline margin. Thalline exciple usually pseudocorticate; proper exciple euthyplectenchymatous to subparaplectenchymatous; hymenium colourless, 85-130 µm high; paraphyses coherent, simple or sparingly branched, 2-3 µm thick at mid-level, the apical cells swollen; hypothecium pale yellow. Asci 8-spored, clavate, the apex thick, with a I+ blue apical dome and a I+ blue annulus projecting downwardly. Ascospores 4-5(-7)-septate, not constricted at septa, hyaline, broadly acicular and irregularly clavate with one end thicker, usually curved, (35-)40-75 x (5-)6-6.5(-7) µm. Pycnidia often numerous, immersed to semi-immersed, on both sides of thallus. Conidia straight, bacilliform or with slightly swollen ends, 4.5-6 x 1-1.8 µm Photobiont cyanobacterial (Nostoc, the cells in long chains). Spot tests: all negative. Chemistry: without lichen substances.
Note: a mild-temperate lichen found on the bark of more or less isolated broad-leaved trees, more thermophytic than the closely related C. nigrescens; presently extinct in northern Italy, except Liguria, still frequent and locally even common in humid sites of Tyrrhenian Italy, especially in Sardegna.
Growth form: Foliose, broad lobed
Substrata: bark
Photobiont: cyanobacteria, filamentous (e.g. Nostoc, Scytonema)
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)

Commonnes-rarity: (info)

Alpine belt: absent
Subalpine belt: absent
Oromediterranean belt: absent
Montane belt: absent
Submediterranean belt: extremely rare
Padanian area: absent
Humid submediterranean belt: rare
Humid mediterranean belt: rather rare
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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Predictive model
Herbarium samples


Felix Schumm – CC BY-SA 4.0
Image from: F. Schumm (2008) - Flechten Madeiras, der Kanaren und Azoren. Beck, OHG - ISBN: 978-3-00-023700-3



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (16315)
2001/12/07



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (16315)
2001/12/07


Triin Aimla; Owner: University of Tartu



P.L.Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (37006)
2008.02.25



P.L.Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (37006)
2008.02.25



P.L.Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (29016)
2008.03.06



P.L.Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (29016)
2008.03.06



P.L.Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (29016)
2008.03.06



P.L.Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (29016)
2008.03.06



Felix Schumm - CC BY-SA 4.0
Image from: F. Schumm (2008) - Flechten Madeiras, der Kanaren und Azoren. Beck, OHG - ISBN: 978-3-00-023700-3



Felix Schumm - CC BY-SA 4.0
Image from: F. Schumm (2008) - Flechten Madeiras, der Kanaren und Azoren. Beck, OHG - ISBN: 978-3-00-023700-3



Felix Schumm - CC BY-SA 4.0
Image from: F. Schumm (2008) - Flechten Madeiras, der Kanaren und Azoren. Beck, OHG - ISBN: 978-3-00-023700-3



Felix Schumm - CC BY-SA 4.0
Image from: F. Schumm (2008) - Flechten Madeiras, der Kanaren und Azoren. Beck, OHG - ISBN: 978-3-00-023700-3


Degelius G. 1954. The lichen genus Collema in Europe: Morphology, Taxonomy, Ecology. Symbolae Bot. Upsal. 13, 2: 1-499.


Degelius G. 1954. The lichen genus Collema in Europe: Morphology, Taxonomy, Ecology. Symbolae Bot. Upsal. 13, 2: 1-499.


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_C/Textes_C5/Collema_subnigrescens.htm
France, Carençon en Vercors- Isère
20/9/015


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_C/Textes_C5/Collema_subnigrescens.htm
France, Carençon en Vercors- Isère
20/9/015


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_C/Textes_C5/Collema_subnigrescens.htm
France, Carençon en Vercors- Isère
20/9/015