Gyalecta truncigena (Ach.) Hepp

Flecht. Eur.: nr. 27, 1853. Basionym: Gyalecta wahlenbergiana var. truncigena Ach. - Lichenogr. Univ.: 152, 1810.
Synonyms: Gyalecta abstrusa (Wallr.) A. Massal.
Distribution: N - VG (Carvalho 1997), Ven, TAA (Nascimbene & al. 2007b), Lomb (Jatta 1909-1911), Lig (Giordani & Incerti 2008). C - Tosc (Tretiach & Nimis 1994, Loppi & al. 1998, Putortì & al. 1998, Stofer 2006, Brunialti & Frati 2010, Benesperi 2011), Marc (Frati & al. 2004, Frati & Brunialti 2006), Umb (Ravera 1998, Ravera & al. 2006), Laz (Massari & Ravera 2002, Munzi & al. 2004, 2007, Ruisi & al. 2005, Genovesi & al. 2008, Ravera & Genovesi 2008, Gagliardi & al. 2010), Abr, Mol (Caporale & al. 2008, Ravera & Genovesi 2010, Ravera & al. 2010, Paoli & al. 2015, Caporale & Ravera 2020), Sar (Zedda 2002, Stofer 2006, Rizzi & al. 2011). S - Camp, Pugl (Nimis & Tretiach 1999), Bas (Bartoli & Puntillo 1998, Potenza 2006, Potenza & al. 2010), Cal (Puntillo 1995, 1996, Sérusiaux 1998, Puntillo & Puntillo 2004), Si (Nimis & al. 1994, Ottonello 1996, Campisi & al. 2020).
Description: Thallus crustose, inconspicuous, thin to scurfy, pale green or grey. Apothecia scattered to aggregated, usually immersed, later sometimes becoming sessile, 0.2-0.7 mm across, with a pale yellow-brown to pale orange or finally dark brown, deeply concave, waxy disc and a smooth to radially cracked, cream-coloured, brownish or yellowish pink proper margin which is sometimes overrun by thallus. Proper exciple thick, colourless or pale brown in outer part; epithecium hardly differentiated from the hymenium; hymenium colourless, 90-115 µm high; paraphyses slightly longer than the asci, septate, capitate, the apical cells up to 3-4 µm wide; hypothecium colourless to pale yellow. Asci 8-spored, cylindrical to elongate-clavate, thin-walled, lacking an apical apparatus or tholus, K/I+ blue. Ascospores muriform (with 6 or more cells visible in optical view) with 4-9 transverse septa and 1-2 longitudinal septa, most septa perpendicular to each other, hyaline, fusiform, without conical tips, (14-)17-28(-31) x 5-9 µm. Photobiont trentepohlioid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a temperate lichen found on mature trees, mostly Acer and Fraxinus, but also on the slightly nutrient-enriched bark of more acid-barked trees such as oaks, in mild-humid areas; more common in the past, presently localised in clearings of ancient, open, humid deciduous forests.
Growth form: Crustose
Substrata: bark
Photobiont: Trentepohlia
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: extremely rare
Submediterranean belt: extremely rare
Padanian area: absent
Humid submediterranean belt: rare
Humid mediterranean belt: absent
Dry mediterranean belt: absent

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples

Felix Schumm – CC BY-SA 4.0
[12544], Germany, Baden-Württemberg, Kreis Göppingen, Albrand, Bad Überkingen, auf dem Pfad zum Kahlenstein, 48°35.892'N, 9°48.493'E, 675 m, auf Esche beim Höhleneingang des Kahlensteins, Schumm, 02.07.2006

P.L.Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (38246)

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (11909)