Helocarpon pulverulum (Th. Fr.) Türk & Hafellner

Carinthia II, 183: 738, 1993. Basionym: Lecidea crassipes f. pulverula Th. Fr. - Lichenogr. Scand., 1: 250, 1874.
Synonyms: Helocarpon crassipes auct. eur. merid. non Th. Fr.; Micarea crassipes auct. eur. merid. non (Th. Fr.) Coppins
Distribution: N - Frl (Tretiach & Hafellner 2000), Ven (Nascimbene & Caniglia 2003c), TAA (Printzen & Rambold 1995, Caniglia & al. 2002, Nascimbene & al. 2022).
Description: Thallus crustose, episubstratic, rather thick, composed of densely packed, pulverulent granules, whitish to partially grey-brown or grey. Apothecia biatorine, black, 0.2-0.6 mm across, strongly constricted at base and sometimes substipitate, with a flat to finally convex disc, and an up to 0.05 mm thick, finally excluded proper margin. Proper exciple thin, of radially arranged hyphae, dark olivaceous green and K+ green in outer part, colourless within; epithecium green to olive and K+ green, or purple-brown and K+ purple; hymenium colourless or pale purple, c. 50 μm high, I+ blue turning red; paraphyses coherent, thin, mostly simple; hypothecium dark purplish brown, K+ slowly purplish, N+ purple-red. Asci 8-spored, cylindrical-clavate, the I+ blue tholus with a wide, I+ dark blue tube structure. Ascospores 1-celled or 1-septate, oblong to subfusiform, rarely ellipsoid, 9-17(-21) x 2.5-5 μm. Pycnidia black, sessile, to 0.15 mm across. Conidia short-bacilliform, to 5.5 μm long. Photobiont micareoid, the cells 4-7 µm across. Spot tests: K-, C-, KC-, P-. UV-. Chemistry: thallus without lichen substances.
Note: on bryophytes and plant debris on the ground and amongst rocks, in areas with siliceous substrata, with optimum near treeline; probably more widespread in the Alps. The species is heterogeneous; according to Hafellner (2001) all material from at least the Eastern Alps is morphologically different from H. crassipes s.str., and belongs instead to H. pulverulum.
Growth form: Crustose
Substrata: soil, terricolous mosses, and plant debris
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

Alpine belt: very rare
Subalpine belt: 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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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
Herbarium samples
Index Fungorum GBIF


P.L. Nimis CC BY-SA 4.0
TSB 37308



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (28560)
2003/03/19



P.L. Nimis CC BY-SA 4.0
TSB 37308



P.L. Nimis CC BY-SA 4.0
TSB 37308



P.L. Nimis CC BY-SA 4.0
TSB 37308



P.L. Nimis CC BY-SA 4.0
TSB 37308



Pier Luigi Nimis - Department of Life Sciences, University of Trieste - CC BY-SA 4.0
TSB 37308



Pier Luigi Nimis - Department of Life Sciences, University of Trieste - CC BY-SA 4.0
TSB 37308



P.L. Nimis CC BY-SA 04
TSB 38067



P.L. Nimis CC BY-SA 04
TSB 38067



P.L. Nimis CC BY-SA 04
TSB 38067