Acolium sessile (Pers.) Arnold

Flora, 68: 49, 1885. Basionym: Calicium sessile Pers. - Tent. Disp. Meth. Fung., Suppl.: 59, 1797.
Synonyms: Cyphelium sessile (Pers.) Trevis
Distribution: N - Lomb (Puntillo & Puntillo 2009, Brackel 2016), Emil (Puntillo & Puntillo 2009, Brackel 2016, Fariselli & al. 2020), Lig (Brunialti & al. 2001, Brackel 2016). C - Tosc (Puntillo & Puntillo 2009, Brackel 2016), Umb (Ravera 2000, Ravera & al. 2006, Brackel 2016), Abr (Corona & al. 2016, Brackel 2016). Mol (Brackel 2020). S - Pugl (Thüs & Licht 2006, Brackel 2016), Cal (Puntillo 1994, 1996, Puntillo & Puntillo 2009, Brackel & Puntillo 2016, Brackel 2016).
Description: Thallus crustose, not lichenized, infecting the thalli of Pertusaria-species, visible as a darkening of the host thallus. Apothecia sessile, 0.25-0.6 mm across, 0.2-0.3 mm high, usually epruinose (young apothecia rarely white-pruinose at margins), with a black mazaedium. Exciple dark brown, 50-90 µm thick laterally, of strongly sclerotized, interwoven hyphae, with an outer, 2-3 µm thick gelatinous layer, strongly thickened at base and often forming a stalk penetrating the thallus of the host; hypothecium dark brown, 40-55 µm high, of periclinally arranged, sclerotized hyphae. Asci narrowly clavate, formed singly from hooked ascogenous hyphae, persisting until the spores are nearly ripe, with biseriately arranged spores. Ascospores 1-septate and constricted at septum, brown, broadly ellipsoid, 10-15 x 6-9 µm, with a coarse ornamentation of mainly spirally arranged ridges in young spores, later disrupted by a few irregular cracks, the surface appearing striated. Photobiont absent. Spot tests: all negative. Chemistry: without lichen substances.
Note: a species with a grey thallus forming insular patches on the thalli of epiphytic Pertusaria-species (especially P. pertusa, P. coccodes and P. coronata), found on very old oaks; also known from North America, it is most common in western Europe: records from the Alps have a fairly different ecology and conspecifity is therefore in need of confirmation.
Growth form: Lichenicolous fungus
Substrata: bark
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)
paras Pertusaria spp.

Commonnes-rarity: (info)

Alpine belt: absent
Subalpine belt: absent
Oromediterranean belt: absent
Montane belt: absent
Submediterranean belt: extremely rare
Padanian area: absent
Humid submediterranean belt: extremely rare
Humid mediterranean belt: absent
Dry mediterranean belt: absent


pH of the substrata:

(info)

1

2

3

4

5

Solar irradiation:

(info)

1

2

3

4

5

Aridity:

(info)

1

2

3

4

5

Eutrophication:

(info)

1

2

3

4

5

Poleotolerance:

(info)

0

1

2

3

Altitudinal distribution:

(info)

1

2

3

4

5





P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (24267)
2001/12/04



Felix Schumm; Owner: CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm; Owner: CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm; Owner: CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Felix Schumm - CC BY-SA 4.0
[TSB_24267], Italia, Calabria, Prov. Catanzaro, loc. Cortale, c. 400 m, on Olea. Leg. D. Puntillo, 02.03.1992 (ex CLU)



Domenico Puntillo - CC BY-SA 4.0
Italy