Collema flaccidum (Ach.) Ach.

Lichenogr. Univ.: 647, 1810. Basionym: Lichen flaccidus Ach. - K. Vetensk.-Akad. Nya Handl., 16: 14, 1795.
Synonyms: Collema atroplumbeum Hue; Collema furvum var. flaccidum (Ach.) Spreng.; Collema rupestre (Sw.) Rabenh.; Lathagrium rupestre (Sw.) A. Massal.; Lichen rupestris Sw. nom. illegit.; Parmelia flaccida (Ach.) Ach.; Synechoblastus flaccidus (Ach.) Körb.; Synechoblastus rupestris (Sw.) Trevis.
Distribution: N - VG (Carvalho 1997), Frl (Tretiach & Hafellner 2000, Tretiach & Molaro 2007), Ven (Caniglia & al. 1999, Nascimbene 2008c), TAA (Philippi 1983, Nascimbene 2005b, Nascimbene & al. 2007b), Lomb (Philippi 1983, Arosio & al. 2003, Valcuvia & al. 2003, De Vita & Valcuvia 2004), Piem (Morisi & Sereno 1995, Isocrono & al. 2004, Isocrono & Piervittori 2008), VA (Valcuvia 2000, Valcuvia & al. 2000b, Piervittori & al. 2001, Matteucci & al. 2015c), Emil (Gasparo & Tretiach 1996, Tretiach & al. 2008, Fariselli & al. 2020), Lig (Giordani & Incerti 2008). C - Tosc (Benesperi & al. 2007, Benesperi 2011, Brackel 2015), Marc (Nimis & Tretiach 1999), Umb (Ravera 1998, Panfili 2000b, Ravera & al. 2006), Laz (Ravera 2001, Massari & Ravera 2002, Ravera & Genovesi 2008), Abr (Olivieri & Pacioni 1996, Olivieri & al. 1997, 1997b, Loppi & al. 1999, Nimis & Tretiach 1999, Caporale & al. 2008, 2016, Brackel 2015, Corona & al. 2016, Gheza & al. 2021), Mol (Frati & al. 2004, Caporale & al. 2008), Sar (Nöske 2000, Zedda 2002, Rizzi & al. 2011, Cossu 2013). S - Camp (Ricciardi & al. 2000, Nimis & Tretiach 2004, Nascimbene & al. 2010b, Garofalo & al. 2010, Brunialti & al. 2013, Ravera & Brunialti 2013), Pugl (Nimis & Tretiach 1999), Bas (Nimis & Tretiach 1999, Potenza 2006, Potenza & Fascetti 2010), Cal (Puntillo 1996), Si (Czezuga & al. 1994, Grillo 1998, Grillo & Caniglia 2004, Liistro & Cataldo 2011, Ottonello & al. 2011).
Description: Thallus foliose, homoiomerous, gelatinous when wet, blackish brown to black, thick, smooth, loosely attached,, to 6 cm diam. (usually less). Lobes (0.5-)1-2(-3) cm broad, rounded, flattened, contiguous, adpressed, with an entire, undulated, not swollen margin. Isidia globular when young, but soon becoming squamiform, diffuse, mostly simple. Upper and lower cortex absent. Apothecia rare, lecanorine, sessile, to 2.5 mm across, with a reddish brown, flat to finally convex disc, and a thin, entire, pseudocorticate thalline margin. Epithecium brownish; hymenium colourless, I+ blue; paraphyses simple or sparingly branched, 2(-4) µm thick, with clavate to subglobose tips; hypothecium colourless. Asci 8-spored, narrowly clavate, the apex thick, with a I+ blue apical dome and a I+ blue annulus projecting downwardly. Ascospores transversely 3-5-septate, hyaline, fusiform-elongate, (20-)25-35(-40) x 6-7 µm. Pycnidia common, usually thicker than thallus. Conidia bacilliform, straight, (3-)4-4.5(-6) x 1-1.5(-2) µm. Photobiont cyanobacterial (Nostoc), in long chains. Spot tests: all negative. Chemistry: without lichen substances.
Note: a mainly temperate to southern boreal-montane lichen with a fragmented holarctic range, found on bark, epilithic mosses, base-rich siliceous and slightly calciferous rocks in sheltered, humid situations; more common in the past and now absent from urban areas and from the Po-Plain; mostly Tyrrhenian in Italy, but still locally frequent in humid Alpine and pre-Alpine areas.
Growth form: Foliose, broad lobed
Substrata: bark and rocks
Photobiont: cyanobacteria, filamentous (e.g. Nostoc, Scytonema)
Reproductive strategy: mainly asexual, by isidia, or isidia-like structures (e.g. schizidia)
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: very rare
Submediterranean belt: extremely rare
Padanian area: absent
Humid submediterranean belt: rather common
Humid mediterranean belt: common
Dry mediterranean belt: extremely 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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P.L. Nimis CC BY-SA 4.0
TSB 15001



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (11346)
2001/12/04


Triin Aimla; Owner: University of Tartu



P.L.Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (15001)
2008.03.06



P.L.Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (15001)
2008.03.06



P.L.Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (15001)
2008.03.06


Antonio Valero; Owner: Antonio Valero
Spain
2010


Antonio Valero; Owner: Antonio Valero
Spain
2010


Antonio Valero; Owner: Antonio Valero
Spain
2010


Domenico Puntillo - CC BY-SA 4.0
Italy
exceptionally fruiting species


Leif Stridvall
Courtesy: Anita Stridvall -Source: http://www.stridvall.se/lichens/gallery/


Leif Stridvall
Courtesy: Anita Stridvall -Source: http://www.stridvall.se/lichens/gallery/


Leif Stridvall
Courtesy: Anita Stridvall -Source: http://www.stridvall.se/lichens/gallery/


Leif Stridvall
Courtesy: Anita Stridvall -Source: http://www.stridvall.se/lichens/gallery/


Leif Stridvall
Courtesy: Anita Stridvall -Source: http://www.stridvall.se/lichens/gallery/


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



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (11346)
2001/12/04


Leif Stridvall Anita Stridvall -Source: http://www.stridvall.se/lichens/gallery/