Rhizocarpon intersitum Arnold

Verh. zool.-bot. Ges. Wien, 27: 554, 1877.
Synonyms: Rhizocarpon diversisporum Hav.
Distribution: N - TAA (Dalla Torre & Sarnthein 1909, Nascimbene & al. 2022).
Description: Thallus crustose, episubstratic, verruculose-areolate, whitish grey, grey or grey-brown, occasionally greenish or pink-tinged, epruinose, delimited by a black prothallus. Areoles contiguous or dispersed, 0.2-0.6(-0.8) mm wide, smooth, flat to strongly convex, angular or more or less round, smooth. Medulla white, I-. Apothecia lecideine, black, 0.25-0.7 mm across, more or less round, innate among the areoles, with a flat to convex, epruinose disc, and a thin, finally excluded proper margin. Proper exciple c. 30 μm thick, dark brown in outer part, paler within, K+ purplish; epithecium greenish brown, K+ intensifying green; hymenium colourless to pale greenish in places, not inspersed, I+ blue; hypothecium dark brown to dark reddish brown. Asci (4-)8-spored, clavate, fissitunicate, with a well-developed tholus, lacking an ocular chamber, Rhizocarpon-type. Ascospores submuriform to muriform, soon blackish green, with 9-18 cells in optical section, ellipsoid, often slightly curved, 20-33 x 8-12 μm. Photobiont chlorococcoid. Spot tests: medulla K- or K+ pale yellow, C-, KC-, P-. Chemistry: without lichen substances, or with variable amounts of stictic acid.
Note: a rather poorly known species found on inclined to vertical faces of acidic siliceous rocks, often near waterfalls, mostly in upland areas.
Growth form: Crustose
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Poorly known taxon in need of further study

Commonnes-rarity: (info)

Alpine belt: very rare
Subalpine belt: very rare
Oromediterranean belt: absent
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

Einar Timdal - Source: http://nhm2.uio.no/lav/web/index.html - CC BY-NC


Einar Timdal - Source: http://nhm2.uio.no/lav/web/index.html - CC BY-NC