Psorotichia murorum A. Massal.

Framm. Lichenogr.: 15, 1855.
Synonyms: Collemopsis murorum (A. Massal.) Stizenb.; Psorotichia arenaticola Eggerth
Distribution: N - Ven (Lazzarin 2000b), TAA, Lomb, Piem, Emil (Fariselli & al. 2020), Lig. C - Tosc, Abr, Sar. S - Pugl, Si.
Description: Thallus crustose, areolate, homoiomerous, pseudoparenchymatous throughout, the hyphae 3-8 µm thick. Areoles 0.25-0.8(-1.2) mm wide, up to 0.3 mm thick, contiguous, brownish black, epruinose, with an uneven, weakly granulose surface. Apothecia at first immersed, then adnate to sessile, 2-6(-8) per areole, 0.1-0.2(-0.3) mm across, with an initially punctiform, then expanded, concave to flat, reddish brown to brown-black disc surrounded by a thick, smooth thalline margin. Proper exciple poorly differentiated, up to 10 µm wide laterally, formed by irregularly anastomosing hyphae; epithecium orange-brown, 10-15 µm high; hymenium colourless, 100-120 µm high, I+ blue; paraphyses branched and anastomosing, with cylindrical cells, 2-3 µm thick, only slightly constricted at septa; hypothecium colourless, 30-50 µm high. Asci 8-spored, cylindrical-clavate, with a rather thick, not amyloid wall, without apical amyloid thickenings, 55-70 x 12-17 µm. Ascospores 1-celled, hyaline, ellipsoid to broadly ellipsoid, (9-)10-16(-18) x (5-)7-9(-10) µm. Photobiont cyanobacterial, chroococcoid, of a few cells measuring 6-12 x 3-7 µm, surrounded by a gelatinous sheath which is yellowish brown near the thallus surface. Spot tests: all negative. Chemistry: without lichen substances.
Note: on sunny surfaces of calcareous rocks, including mortar, mostly below the montane belt.
Growth form: Crustose
Substrata: rocks
Photobiont: cyanobacteria, filamentous (e.g. Nostoc, Scytonema)
Reproductive strategy: mainly sexual
On otherwise dry surfaces with short periods of water seepage after rain
Poorly known taxon in need of further study

Commonnes-rarity: (info)

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

pH of the substrata:

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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

Author: André Aptroot - Source: http://www.tropicallichens.net/ CC BY-SA-NC