Placidium lachneum (Ach.) B. de Lesd.

Ann. Cryptog. Exot., 5: 100, 1932. Basionym: Lichen lachneus Ach. - Lichenogr. Suec. Prodr.: 140, 1799.
Synonyms: Catapyrenium lachneum (Ach.) R. Sant.; Dermatocarpon lachneum (Ach.) A.L. Sm.; Endopyrenium lachneum (Ach.) Hav.
Distribution: N - Frl (TSB 16129), Ven (Nascimbene 2008c), TAA, Lomb (Ravera & al. 2022b), Piem (Hafellner & al. 2004), VA (Piervittori & al. 2004). C - Umb (Genovesi & al. 2002, Ravera & al. 2006), Laz (Herb. Ravera 4891), Abr (Nimis & Tretiach 1999, Di Nuzzo & al. 2021, Gheza & al. 2021, Vallese & al. 2022).
Description: Thallus squamulose, the squamules 2-6(-8) mm broad, 0.24-0.6 mm thick, rounded to crenate, flattened to mostly concave, smooth, with a thicker, up-turned, often darker margin; upper surface medium reddish brown to dark brown, dull; lower surface black, attached by 5-8 µm thick, mostly pale rhizohyphae. Upper cortex paraplectenchymatous, 40-60 µm thick, with a very thin or without an epinecral layer; medulla prosoplectenchymatous of filamentous, 3-5 µm thick hyphae; lower cortex clearly delimited from the medulla, 30-125 µm thick, of (8-)15-28 µm wide, angular cells arranged in vertical rows, the lowermost ones with a black pigment. Perithecia laminal, broadly pyriform, up to 0.6 mm wide, immersed in the squamules, without involucrellum. Exciple pale throughout; paraphyses absent, substituted by periphyses; hymenium K/I+ blue. Asci 8-spored, cylindrical, thin-walled, non-amyloid and without an ocular chamber. Ascospores 1-celled, hyaline, ellipsoid, thin-walled, 12-18 x 6-8 μm, uniseriately arranged in the asci. Pycnidia marginal, prominent and knotty, black, 200-400(-600) µm in diam. Conidia bacilliform, 5-7 x 1-2 μm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a mainly boreal-montane to arctic-alpine, circumpolar lichen found on terricolous bryophytes and on more or less organic calciferous soil in upland areas, reaching the nival belt in the Alps, also occurring in the central Apennines.
Growth form: Squamulose
Substrata: soil, terricolous mosses, and plant debris
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

Alpine belt: rather common
Subalpine belt: rather rare
Oromediterranean belt: 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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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


P.L. Nimis CC BY-SA 04
TSB 32933



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (32933)
2003/02/14



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (32933)
2001/12/08


Luca di Nuzzo CC BY 4.0
Italy, Lombardy, Bergamo, Vilminore di Scalve, Leg.: Gabriele Gheza. Det.: Luca di Nuzzo
09.2021


Luca di Nuzzo CC BY 4.0
Italy, Lombardy, Bergamo, Vilminore di Scalve, Leg.: Gabriele Gheza. Det.: Luca di Nuzzo
09.2021


Luca di Nuzzo CC BY 4.0
Italy, Lombardy, Bergamo, Vilminore di Scalve, Leg.: Gabriele Gheza. Det.: Luca di Nuzzo
09.2021


Luca di Nuzzo CC BY 4.0
Italy, Lombardy, Bergamo, Vilminore di Scalve, Leg.: Gabriele Gheza. Det.: Luca di Nuzzo
09.2021


Luca di Nuzzo CC BY 4.0
Italy, Lombardy, Bergamo, Vilminore di Scalve, Leg.: Gabriele Gheza. Det.: Luca di Nuzzo
09.2021


Luca di Nuzzo CC BY 4.0
Italy, Lombardy, Bergamo, Vilminore di Scalve, Leg.: Gabriele Gheza. Det.: Luca di Nuzzo
09.2021


Luca di Nuzzo CC BY 4.0
Italy, Lombardy, Bergamo, Vilminore di Scalve, Leg.: Gabriele Gheza. Det.: Luca di Nuzzo
09.2021


Luca di Nuzzo CC BY 4.0
Italy, Lombardy, Bergamo, Vilminore di Scalve, Leg.: Gabriele Gheza. Det.: Luca di Nuzzo
09.2021


Luca di Nuzzo CC BY 4.0
Italy, Lombardy, Bergamo, Vilminore di Scalve, Leg.: Gabriele Gheza. Det.: Luca di Nuzzo
09.2021


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_P/Text_P_2/Placidium_lachneum.htm
France, 29/8/2013 - Mont Cenis - Carrière du Paradis - Savoie


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_P/Text_P_2/Placidium_lachneum.htm
France, 29/8/2013 - Mont Cenis - Carrière du Paradis - Savoie


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_P/Text_P_2/Placidium_lachneum.htm
France, 29/8/2013 - Mont Cenis - Carrière du Paradis - Savoie


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_P/Text_P_2/Placidium_lachneum.htm
France, 29/8/2013 - Mont Cenis - Carrière du Paradis - Savoie


Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_P/Text_P_2/Placidium_lachneum.htm
France, 29/8/2013 - Mont Cenis - Carrière du Paradis - Savoie