ITALIC 8.0

Rhizocarpon geographicum subsp. arcticum (Runemark) Hertel

in Hertel & Ullrich, Mitt. bot. Staatss. München, 12: 483, 1976. Basionym: Rhizocarpon tinei subsp. arcticum Runemark - Opera Bot., 2: 125, 1956.

Synonyms:

Distribution: N - TAA (Nascimbene & al. 2022), VA (Piervittori & Isocrono 1999).

Description: Thallus crustose, whitish yellow-green, 0.2-0.6 mm thick, areolate, forming patches to 5 cm diam., delimited by a black prothallus. Areoles more or less angular, 0.2-1.3 mm wide, flat to convex, smooth, not subdivided by cracks, contiguous or often dispersed on a black hypothallus. Cortex without distinct structure, with abundant small crystals not soluble in K; medulla white, I+ blue. Apothecia frequent, lecideine, arising between the areoles and often surrounded by collar-like areoles, rounded, 0.5-1 mm across, with a black, weakly concave to weakly convex, epruinose disc, and a very thin, often indistinct, black proper margin. Proper exciple pale brown to brownish red; epithecium brown, K-; hymenium 100-150 µm thick, colourless to greenish, K/I+blue, K+ greenish; paraphysoids strongly conglutinate, richly branched and anastomosing, sometimes slightly capitate; hypothecium dark brown, K-. Asci 8-spored, clavate, fissitunicate, with a well-developed tholus, lacking an ocular chamber, Rhizocarpon-type. Ascospores muriform, with 6-13 cells visible in optical view, soon becoming dark green to brown, ellipsoid, 22-30 x 10-16 µm, halonate. Photobiont chlorococcoid. Spot tests: medulla K-, C-, KC- , P- or rarely P+ yellow. Chemistry: rhizocarpic acid.

Note: an arctic-alpine lichen found on siliceous, exposed rocks, restricted to the nival belt of the Alps.

Growth form: Crustose

Substrata: rocks

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

Alpine belt: very rare

Subalpine belt: absent

Oromediterranean belt: absent

Montane belt: absent

Submediterranean belt: absent

Padanian area: absent

Humid submediterranean belt: absent

Humid mediterranean belt: absent

Dry mediterranean belt: absent

pH of the substrata:

1

2

3

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

2

3

4

5

6

(info)

Predictive model

Herbarium samples

Index Fungorum GBIF

P.L. Nimis CC BY-SA 4.0

TSB 28423

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

Herbarium: TSB (28423)