ITALIC 8.0

Verrucaria margacea (Wahlenb.) Wahlenb.

Fl. Lappon.: 465, 1812. Basionym: Thelotrema margaceum Wahlenb. in Ach. - Meth. Lich. Suppl.: 30, 1803.

Synonyms: Lithocia margacea (Wahlenb.) A. Massal.; Verrucaria applanata Hepp; Verrucaria divergens Nyl.?; Verrucaria filarszkyana Szatala; Verrucaria leightonii Hepp non A. Massal.; Verrucaria tiroliensis Zschacke; Verrucaria vallis-flueelae Zschacke?

Distribution: N - Ven, TAA (Dalle Vedove & al. 2003, Nascimbene & al. 2007b, 2022, Nascimbene 2008b), Lomb (Nascimbene 2006), Piem (Isocrono & al. 2004), VA (Herb. Nascimbene 2138), Emil (Fariselli & al. 2020). C - Tosc.

Description: Thallus crustose, episubstratic, continuous or cracked especially around the perithecia, smooth to uneven, pale to dark brown or grey-brown, 15-70 μm thick, not distinctly subgelatinous when wet, sometimes delimited by a thin whitish prothallus. Cortex poorly developed; algal layer paraplectenchymatous; medulla poorly developed, proso- to paraplectenchymatous, without a dark basal layer. Perithecia almost completely covered with a thin thalline layer, forming 0.45-0.8(-1.3) mm wide projections, the apical part finally often naked. Involucrellum 12-40 μm thick, conical, reaching to base-level and there spreading, the space between its base and the exciple colourless or often with a dark pigment which is evenly distributed through the cell walls; exciple 0.15-0.27 x 0.16-0.33 mm, the wall colourless to brown; hamathecium of 20-40 μm long periphyses and periphysoids, interascal filaments absent; hymenial gel hemiamyloid, I+ red (I+ blue at very low concentrations of I), K/I+ blue. Asci 8-spored, pyriform to obovate, I-, fissitunicate, the wall thickened above, with an ocular chamber, dehiscent by extrusion of an endotunica to form a delicate rostrum, Verrucaria-type. Ascospores 1-celled, hyaline, ellipsoid, (20-)26-33(-41) x (8-)11-14(-18) μm. Photobiont chlorococcoid, the cells not arranged in vertical columns. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.

Note: an amphibious freshwater lichen of siliceous rocks beside streams and lakes; it prefers constantly inundated and even permanently submerged rocks to those merely in the spray zone. The species seems to be widespread in Scandinavia and is also known from the Southern Hemisphere. The records from Emilia and Tuscany (see Nimis 1993: 743) are particularly dubious.

Growth form: Crustose

Substrata: rocks

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

Periodically submerged (e.g. in creeks)

Commonnes-rarity: (info)

Alpine belt: extremely rare

Subalpine belt: rare

Oromediterranean belt: absent

Montane belt: very rare

Submediterranean belt: absent

Padanian area: absent

Humid submediterranean belt: absent

Humid mediterranean belt: absent

Dry mediterranean belt: absent

pH of the substrata:

1

2

3

4

5

(info)

Solar irradiation:

1

2

3

4

5

(info)

Aridity:

1

2

3

4

5

(info)

Eutrophication:

1

2

3

4

5

(info)

Poleotolerance:

0

1

2

3

(info)

Altitudinal distribution:

1

2

3

4

5

6

(info)

Predictive model

Herbarium samples

Index Fungorum GBIF

Juri Nascimbene - CC BY-SA 4.0

Stelvio National Park, Reg. Trentino-Alto Adige Prov. Trento, Italy.
07.2005

Juri Nascimbene - CC BY-SA 4.0

Stelvio National Park, Reg. Trentino-Alto Adige Prov. Trento, Italy.
07.2005

P.L. Nimis CC BY-SA 04

TSB 16078

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste

Herbarium: TSB (16078)
2001/12/03

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_V/Texte_V/Verrucaria_margacea.htm

France, 25/8/2018 - Col du Petit Mont Cenis, alt. 2200 m - Savoie

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_V/Texte_V/Verrucaria_margacea.htm

France, 25/8/2018 - Col du Petit Mont Cenis, alt. 2200 m - Savoie

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_V/Texte_V/Verrucaria_margacea.htm

France, 25/8/2018 - Col du Petit Mont Cenis, alt. 2200 m - Savoie

Zschacke, H. (1934) Epigloeaceae, Verrucariaceae und Dermatocarpaceae. In: Dr. L. Rabenhorst‘s Kryptogamen-Flora, Band 9, Abt. 1, Teil 1. Akademische Verlagsgesellschaft, Leipzig, 695 pp. - Public Domain

Zschacke, H. (1934) Epigloeaceae, Verrucariaceae und Dermatocarpaceae. In: Dr. L. Rabenhorst‘s Kryptogamen-Flora, Band 9, Abt. 1, Teil 1. Akademische Verlagsgesellschaft, Leipzig, 695 pp. - Public Domain