Acarospora hospitans H. Magn.

Göteb. Vetensk.-och Vitter.-Handl., ser. 4, 28, 2: 111, 1924.
Synonyms: Acarospora impressula var. hospitans (H. Magn.) Clauzade & Cl. Roux
Distribution: N - TAA (Pl. Graec. Lich. 182), Piem (TSB 34163), Emil (Fariselli & al. 2020). C - Sar (Brackel & Berger 2019). S - Bas (Nimis & Tretiach 1999), Cal (Puntillo 1996), Si (Poli & al. 1995, Nimis & al. 1996b, Grillo & Caniglia 2004, Brackel 2008c).
Description: Thallus crustose, episubstratic, chestnut brown to dark brown, areolate-subsquamulose, forming small islands or lines on the thalli of other crustose lichens, the areoles dispersed or contiguous, 0.3-1.5(-1.8) mm wide, smooth, usually slightly glossy, flat or moderately convex; lower side pale. Upper cortex (20-)30-40(-60) µm thick, brown in upper part, colourless in lower part, the cells 1.5-2.5 μm wide, overlain by a thin amorphous layer; algal layer regular, usually continuous; medulla white, inspersed with crystals. Apothecia lecanorine, of different shapes but most often elongate, 0.1-1.5 x 0.1-1.2 mm, immersed in the areoles, usually 2-5 per areole, with a brown, concave to flat disc, and a thin, sometimes poorly evident thalline margin. Proper exciple 15-20 µm thick; epithecium red-brown; hymenium colourless, (50-)75-90(-100) µm high, the hymenial gel euamyloid, IKI+ persistently dark blue; paraphyses 1.5-2 µm thick at base, the apical cells 3-3.5 µm wide; hypothecium colourless, c. 30 µm high. Asci c. 100-spored, clavate, the apical dome K/I-. Ascospores 1-celled, hyaline, broadly ellipsoid, 3-5 x 2-3 µm. Pycnidia immersed. Conidia ellipsoid, 1-2 x 0.7-1.5 µm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on siliceous rocks, growing on the thalli of other crustose lichens, according to Roux (in litt.) exclusively on Aspicilia spp. Much overlooked, and in need of further study, this species, which is apparently similar to A. impressula, does not belong to Acarospora s.str. (Westberg & al. 2015).
Growth form: Crustose
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
paras Aspicilia spp.
Poorly known taxon in need of further study

Commonnes-rarity: (info)

Alpine belt: rare
Subalpine belt: rather rare
Oromediterranean belt: very rare
Montane belt: rare
Submediterranean belt: extremely rare
Padanian area: absent
Humid submediterranean belt: extremely rare
Humid mediterranean belt: extremely rare
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
Index Fungorum GBIF


Domenico Puntillo; Owner: Domenico Puntillo
Italy, Herb. Puntillo



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (35208)
2002/07/09
on the host, Aspicilia sp.



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (35208)
2002/07/09
on the host, Aspicilia sp.



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (35208)
2002/07/09
on the host, Aspicilia sp.


Magnusson A. H. (1935) Acarosporaceae, Thelocarpaceae. - In: Rabenhorst G. L.: Kryptogamen-Flora von Deutschland, Österreich, und der Schweiz-. 2nd- IX. Die Flechten. Abt. 5- 1. Gebr. Borntraeger. Leipzig, pp. 1-318. – Public Domain