ITALIC 8.0

Rhizocarpon geographicum subsp. lindsayanum (Räsänen) Ahti

Norrlinia, 17: 57, 2008. Basionym: Rhizocarpon lindsayanum Räsänen - Rev. Sudam. Bot., 7: 87, 1942.

Synonyms: Rhizocarpon riparium subsp. lindsayanum (Räsänen) J.W. Thomson

Distribution: N - VG (TSB 11681). S - Si.

Description: Thallus crustose, yellow-green, areolate, forming patches to 10 cm diam., delimited by a black prothallus which is often visible also as a hypothallus between areoles. Areoles round to angular, 0.4-2.5 mm diam., dispersed to usually contiguous, flat, more rarely slightly concave to slightly convex, smooth, epruinose. Cortex 25-40 µm thick, without distinct structure, with abundant small crystals not soluble in K; medulla white, I+ blue. Apothecia frequent, lecideine, arising between the areoles, round or angular, to 1.3 mm across., with a black, weakly concave to weakly convex, epruinose disc, and a very thin, usually persistent and slightly raised, sometimes finally excluded, black proper margin. Proper exciple pale brown to brownish red; epithecium brown, K-; hymenium 120-200 µm thick, colourless to greenish, K/I+blue, K+ greenish; paraphysoids strongly conglutinated, 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 many septa, soon becoming dark green to brown, ellipsoid, 24-40 x 11-15 µm, halonate. Photobiont chlorococcoid. Spot tests: medulla K-, C-, KC- , P- or P+ yellow. Chemistry: cortex with rhizocarpic acid; medulla with and either psoromic or barbatic acid.

Note: this subspecies seems to have a circumboreal distribution. It is found on siliceous, often dust-impregnated rocks, also on walls and boulders in semi-urban environments. It certainly occurs also in the Alps, but was rarely distinguished from Rh. geographicum s.lat.

Growth form: Crustose

Substrata: rocks

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: very rare

Oromediterranean belt: very rare

Montane belt: very rare

Submediterranean belt: very rare

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

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_R/Textes_R2/Rhizocarpon_geographicum_lindsayanum.htm

France, 21/7/2014 - Jausiers - Alpes-de-Haute-Provence - (04) - en bordure du lac des Sagnes, alt. 1900 m

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_R/Textes_R2/Rhizocarpon_geographicum_lindsayanum.htm

France, 21/7/2014 - Jausiers - Alpes-de-Haute-Provence - (04) - en bordure du lac des Sagnes, alt. 1900 m

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_R/Textes_R2/Rhizocarpon_geographicum_lindsayanum.htm

France, 21/7/2014 - Jausiers - Alpes-de-Haute-Provence - (04) - en bordure du lac des Sagnes, alt. 1900 m

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_R/Textes_R2/Rhizocarpon_geographicum_lindsayanum.htm

France, 21/7/2014 - Jausiers - Alpes-de-Haute-Provence - (04) - en bordure du lac des Sagnes, alt. 1900 m

Courtesy Danièle et Olivier Gonnet - Source: https://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_R/Textes_R2/Rhizocarpon_geographicum_lindsayanum.htm

France, 21/7/2014 - Jausiers - Alpes-de-Haute-Provence - (04) - en bordure du lac des Sagnes, alt. 1900 m

P.L. Nimis CC BY-SA 4.0

TSB 11681