Rhizocarpon pusillum Runemark

Opera Bot., 2: 63, 1956.
Synonyms:
Distribution: N - Frl (Tretiach & Hafellner 2000), TAA, Lomb, Piem.
Description: Thallus crustose, areolate, bright yellow-green to whitish yellow, forming 0.3-1 cm wide patches within the thallus of Sporastatia-species, without a clear prothallus. Areoles developing from those of the host, round to angular, contiguous, the peripheral ones not elongate, slightly to strongly convex, 0.2-0.6 mm wide, smooth, sometimes slightly farinose. Cortex poorly differentiated, 40-75 µm thick; medulla white, I-. Apothecia lecideine, black, round or angular, 0.3-0.7 mm across, with a flat to convex, epruinose disc and a soon excluded proper margin. Proper exciple reddish brown in outer part, K+ reddish-violet; epithecium reddish brown, K+ reddish, with dark crystals; hymenium colourless, 60-100 µm high; apices of paraphysoids capitate; hypothecium brown, K-. Asci 8-spored, clavate, fissitunicate, with a well-developed tholus, lacking an ocular chamber, Rhizocarpon-type. Ascospores 1-septate, at first hyaline or pale green-brown, soon becoming dark green to brown, ellipsoid, 9-14(-18) x (4-)6-7(-8) µm, halonate. Photobiont chlorococcoid. Spot tests: medulla K-, C-, KC-, P+ yellow. Chemistry: rhizocarpic and psoromic acids.
Note: an arctic-alpine, circumpolar lichen related to Rh. effiguratum, found on exposed surfaces of hard siliceous rocks, starting the life-cycle on species of Sporastatia; probably restricted to the Alps, where it reaches the nival belt.
Growth form: Crustose
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
In underhangs rarely wetted by rain
paras Sporastatia spp.

Commonnes-rarity: (info)

Alpine belt: rather rare
Subalpine belt: very rare
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:

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(info)

Solar irradiation:

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(info)

Aridity:

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Eutrophication:

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Poleotolerance:

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Altitudinal distribution:

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Predictive model
Herbarium samples
Index Fungorum GBIF


P.L. Nimis CC BY-SA 04
TSB 34345



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (34345)
2002/01/07



Pier Luigi Nimis CC BY-SA 4.0
TSB 41145



Pier Luigi Nimis CC BY-SA 4.0
TSB 41145



Pier Luigi Nimis - CC BY-SA 4.0
TSB 38614



Pier Luigi Nimis - CC BY-SA 4.0
TSB 44047



Pier Luigi Nimis - CC BY-SA 4.0
TSB 44047



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (34345)
2002/01/07
on the host, Sporastatia testudinea



P.L. Nimis CC BY-SA 04
TSB 34345