Pleopsidium chlorophanum (Wahlenb. in Ach.) Zopf

Ann. Chem. 284: 117 (1895).

Basionym: Parmelia chlorophana Wahlenb. in Ach., Methodus Lich. Suppl.: 44 (1803).


Thallus: areolate or squamulose,orbicular, up to 2 cm wide, the margin + distinctly effigurate. Areoles or squamules to 3 mm wide, marginal lobes poorly developed, 0.5-1(-2) mm long, up to 1 mm thick. Upper surface yellow-orange, epruinose. Upper cortex 40-60 µm,cells various. Algal layer even. Apothecia numerous, usually one per areole, 1-3 mm wide; disc pale yellow, lecanorine, flat, becoming convex and the margin excluded, biatorine. Parathecium 50-80 µm thick, narrowing in hypothecium. Hymenium hyaline, 50-70 µm high. Epihymenium yellow-brown. Paraphyses ca. 2 µm wide at mid-level, apices barely expanded. Asci 70-80 x 15-20 µm, clavate; ascospores 100-200 per ascus, hyaline, simple, ellipsoid, 3.5-4.5 x 1.5-2 µm. Pycnidia immersed; conidia, ellipsoid, 3-4 x 1.5-2 µm (Knudsen et al. 2008: 13).

Photobiont: Trebouxioid green alga.

Chemistry: Cortex and medulla K-, C-, KC-, PD- (xxx). Thallus K-, C-, P-, I-; hypothecium I+ brownish yellow or pale blue; hymenium I+ dark blue (Thomson 1997: 23). Rhizocarpic acid (Zopf 1895: xx).
Race I: Acaranoic acid, acarenoic acid (Huneck & Höfle 1980: 2713, Huneck & Yoshimura 1996: 141). (Rhizocarpic acid, pulvic acid (trace), acarano acid, acareno acid (Kümmerling 1991: 95). Rhizocarpic acid, acarano acid, acareno acid (Huneck 1980: 241, Hafellner 1993: 297). Spot tests negative, rhizocarpic acid (major), acaranoic acid (minor), and acarenoic acid (minor) (Knudsen et al. 2008: 13)
Race II: Roccellic acid instead of acarano acid and acareno acid (Huneck 1980: 241). Roccellic acid is thought to be the precursor of both.

Ecology: An regengeschützten, beschatteten Überhangflächen auf saurem, bisweilen glimmer- und eisenreichem Silikatgestein, meist an windoffenen, luftfeuchten Stellen (Wirth 1980: 92). On rocks and on cliffs, especially under oberhangs (Thomson 1997: 23).

Molecular data: Genbank

Distribution: Circumpolar Northern Hemisphere. Database

Author names:
Acarospora chlorophana (Wahlenb. ex Ach.) Mass. in Huneck & Höfle (1980: 2714), Thomson 1997: 20
Pleopsidium chlorophanum (Wahlenb. ex Ach.) Zopf in McCune 2007
Pleopsidium chlorophana (Wahlenb. ex Ach.) Hafellner in Huneck & Yoshimura (1996: 141)
Pleopsidium chlorophanum (Wahlenb.) Zopf in Knudsen et al. (2008: 13), Wirth et al. (2011: 60), Index Fungorum (18.8.2016)

"In 1895, Zopf isolated from the lichen Acarospora chlorophana a compound, pleopsidic acid. Later, Santesson (1993) recognized pleopsidic acid as a mixture of two components which he named acaranoic and acarenoic acids and for which he put forward the gamma-lactone structures 1 and 2. ... We have reexamined acaranoic and acarenoic acids and now propose the delta-lactone structures 3 and 4 for the two compounds" (Huneck & Höfle 1980: 2713).