Collema flaccidum (Ach.) Ach. | Dolichens

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.

Description: Thallus foliose, homoiomerous, gelatinous when wet, blackish brown to black, 70-170(-200) µm thick when wet, smooth, loosely attached, up to 6 cm in diam. (usually less). Lobes (0.5-)1-2(-3) cm broad, rounded at apex, flattened, contiguous, appressed, with an entire, undulate, not swollen margin, with isidia-like outgrowths that are globular when young, but soon become flattened and squamiform, 0.2-0.5(-0.8) mm wide, diffuse and mostly simple. Lower surface usually paler, with sparse white hapters. Upper and lower cortex absent. Apothecia rare, lecanorine, sessile and constricted at base, up to 2.5(-3) mm across, with a reddish brown, epruinose or white-pruinose, flat to finally convex disc and a thin, entire, smooth, persistent or finally excluded thalline margin. Thalline exciple pseudocorticate; proper exciple subparaplectenchymatous to rarely almost euthyplectenchymatous; epithecium brownish; hymenium colourless, 90-130 µm high, I+ blue; paraphyses simple or sparingly branched, 2(-4) µm thick, with clavate to subglobose tips; hypothecium colourless. Asci 8-spored, cylindrical-clavate, the apex strongly thickened, the apical dome K/I+ pale blue, with a downwardly projecting K/I+ deep blue tubular structure. Ascospores transversely 3-5-septate, hyaline, fusiform-elongate, (20-)25-35(-40) x 6-7 µm. Pycnidia common, usually thicker than thallus. Conidia bacilliform, sometimes slightly thickened at the ends, straight, (3-)4-4.5(-6) x 1-1.5(-2) µm. Photobiont cyanobacterial (Nostoc, the cells in long chains). Spot tests: all negative. Chemistry: without lichen substances.

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

Montane belt: very rare

Dry submediterranean belt: extremely rare

Humid submediterranean belt: rather common

Padanian area: absent

pH of the substrata:

1

2

3

4

5

Solar irradiation:

1

2

3

4

5

Aridity:

1

2

3

4

5

Eutrophication:

1

2

3

4

5

Poleotolerance:

0

1

2

3

Altitudinal distribution:

1

2

3

4

5

6

Rarity

absent

extremely rare

very rare

rare

rather rare

rather common

common

very common

extremely common

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Occurrence data

Predictive map

Model Image

Current prediction (1981-2010)

Model Image

Future prediction (2071-2100) SSP 1-2.6

Model Image

Future prediction (2071-2100) SSP 5-8.5

Predictive maps according to Francesconi et al. 2025

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

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/

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/

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_C/Collema_flaccidum.htm; Owner: -

France, session AFL 2015 dans le Lot, Autoire

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_C/Collema_flaccidum.htm; Owner: -

France, session AFL 2015 dans le Lot, Autoire

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_C/Collema_flaccidum.htm; Owner: -

France, session AFL 2015 dans le Lot, Autoire

Bernard Bouffinier - Source: https://italic.units.it/index.php?procedure=images2&taxon=1129

France, Cranou

Bernard Bouffinier - Source: https://italic.units.it/index.php?procedure=images2&taxon=1129

France, Cranou

Bernard Bouffinier - Source: https://italic.units.it/index.php?procedure=images2&taxon=1129

France, Source de la Bidouze

Bernard Bouffinier - Source: https://italic.units.it/index.php?procedure=images2&taxon=1129

France, Source de la Bidouze

Michel David - Source: https://italic.units.it/index.php?procedure=images2&taxon=1129

France, Landevennec, Abbaye

Michel David - Source: https://italic.units.it/index.php?procedure=images2&taxon=1129

France, Landevennec

Michel David - Source: https://italic.units.it/index.php?procedure=images2&taxon=1129

France, Landevennec

Bernard Bouffinier - Source: https://italic.units.it/index.php?procedure=images2&taxon=1129

France, Cranou

Bernard Bouffinier - Source: https://italic.units.it/index.php?procedure=images2&taxon=1129

France, Cranou

Ulrich Kirschbaum CC BY-SA 4.0 - Source: https://www.thm.de/lse/ulrich-kirschbaum/flechtenbilder

Austria; Alps: Kärnten.

Ulrich Kirschbaum CC BY-SA 4.0 - Source: https://www.thm.de/lse/ulrich-kirschbaum/flechtenbilder

Austria; Alps: Kärnten.

Felix Schumm - CC BY-SA 4.0

[VZ1257], Hungaria. Montes Matra, regio montis Agasvár, in vallerivuli Csörgö, 480 m. Ad saxa andesitica. Leg. G. Kiszely, T. Pócs et A.Vezda, 5.06.1974. - EX A. VEZDA: LICHENES SELECTI EXSICCATI NR.1257

Felix Schumm - CC BY-SA 4.0

[VZ1257], Hungaria. Montes Matra, regio montis Agasvár, in vallerivuli Csörgö, 480 m. Ad saxa andesitica. Leg. G. Kiszely, T. Pócs et A.Vezda, 5.06.1974. - EX A. VEZDA: LICHENES SELECTI EXSICCATI NR.1257

Felix Schumm - CC BY-SA 4.0

[VZR470], Germania. Bavaria, Berchtesgadener Land, Königsee, St.Bartholomä, 610 m. Ad corticem arboris (Tilia platyphyllos). Leg. &det. R. Türk & H. Wunder, 11.04.1989 - EX A. VEZDA: LICHENES RARIORES EXSICCATI NR. 470.

Felix Schumm - CC BY-SA 4.0

[VZR470], Germania. Bavaria, Berchtesgadener Land, Königsee, St.Bartholomä, 610 m. Ad corticem arboris (Tilia platyphyllos). Leg. &det. R. Türk & H. Wunder, 11.04.1989 - EX A. VEZDA: LICHENESRARIORES EXSICCATI NR. 470.

Wolfgang von Brackel - CC BY-4.0

Germany, Bavaria, Elmaubachtal

Wolfgang von Brackel - CC BY-4.0

Germany, Bavaria, Elmaubachtal

Collezione lichenologica Abramo Massalongo del Museo di Storia Naturale G. Ligabue di Venezia - Autori: Seggi, Linda; Trabucco, Raffaella Proprietà: Fondazione Musei Civici di Venezia - CC BY-NC

Italy, Veneto, in nem. Montello
As Letagrium rupestre

CC BY 4.0 - Source: Košuthová A, Jonsson F, Nordin U, Wedin M (2025) Phylogeny of the European Collema species (Peltigerales, Lecanoromycetes). MycoKeys 115: 209-220. https://doi.org/10.3897/mycokeys.115.144718

UPS-L872188

Manuel Gil

Spain, Canary Islands, Tenerife
on soil

Manuel Gil

Spain, Canary Islands, Tenerife
on soil

Manuel Gil

Spain, Canary Islands, Tenerife
on soil

Manuel Gil

Spain, Canary Islands, Tenerife
on soil

Manuel Gil

Spain, Canary Islands, Tenerife
on soil

Manuel Gil

Spain, Canary Islands, Tenerife
on soil

Triin Aimla; Owner: University of Tartu

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

Bologna

Biome

Pon

Trieste

Trieste

Paneveggio

Pnab

Pndb