ITALIC 8.0

Rhizocarpon geographicum subsp. diabasicum (Räsänen) Poelt & Vězda

in Hawksworth & al., Lichenologist, 12: 107, 1980. Basionym: Rhizocarpon diabasicum Räsänen - Ann. Bot. Soc. Zool.-Bot. Fenn. Vanamo, 19: 9, 1944.

Synonyms: Rhizocarpon amphiboliticum Räsänen; Rhizocarpon havaasii Räsänen; Rhizocarpon tinei subsp. diabasicum (Räsänen) Runemark

Distribution: N - TAA (Nascimbene & al. 2022), Lomb, Piem (Gheza & Nascimbene 2024). S - Si.

Description: Thallus crustose, episubstratic, bright yellow-green, areolate, forming 2-12 cm wide patches delimited by a black prothallus which is often visible also as a hypothallus between areoles. Areoles angular, 0.4-1(-2) mm wide, 0.4-0.9 mm thick, contiguous, often slightly convex, smooth, epruinose, sometimes forming a crescent-shaped collar around the apothecia. Cortex without a distinct structure; medulla white, I+ blue. Apothecia frequent, lecideine, arising between the areoles, round to angular, 0.5-1(-1.2) mm across, with a black, flat to weakly convex, epruinose disc and a distinct, usually long-persistent proper margin. Proper exciple pale brown to brownish red, K+ red; epithecium reddish brown to reddish violet, K+ distinctly purple-red; hymenium 140-180 µm thick, colourless to greenish, K/I+ blue, K+ greenish; paraphysoids strongly coherent, richly branched and anastomosing, the apical cells clavate; hypothecium dark brown, K-. Asci 8-spored, clavate, fissitunicate, with a well-developed tholus that is K/I- in lower part and K/I+ blue near the apex, lacking an ocular chamber, Rhizocarpon-type. Ascospores muriform, with 12-14 cells visible in optical view, soon becoming dark green to brown, ellipsoid, 28-40 x 10-17 µm, halonate at least when young. Photobiont chlorococcoid. Spot tests: medulla K-, C-, KC-, P+ yellow. Chemistry: cortex with rhizocarpic acid, medulla with psoromic acid.

Note: on siliceous rocks, sometimes also on superficially decalcified calcareous rocks, where it appears in forms with a whitish thallus, near and above treeline.

Growth form: Crustose

Substrata: rocks

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

Alpine belt: very rare

Subalpine belt: very rare

Oromediterranean belt: very rare

Montane belt: extremely rare

Submediterranean belt: extremely rare

Padanian area: absent

Humid submediterranean belt: absent

Humid mediterranean belt: absent

Dry mediterranean belt: absent

pH of the substrata:

1

2

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4

5

(info)

Solar irradiation:

1

2

3

4

5

(info)

Aridity:

1

2

3

4

5

(info)

Eutrophication:

1

2

3

4

5

(info)

Poleotolerance:

0

1

2

3

(info)

Altitudinal distribution:

1

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3

4

5

6

(info)

Predictive model

Herbarium samples

INDEX FUNGORUM GBIF DOLICHENS

P.L. Nimis CC BY-SA 4.0

TSB 14328

Pier Luigi Nimis; Owner: Department of Life Sciences, University of Trieste

Herbarium: TSB (14328)