TYPE. “An Sandsteinblöcken in einem Waldbach bei Heidelberg von den Hrn. V. Zwackh und Ahles gesammelt.” (Koerber 1865). GERMANY. Baden-Württemberg, in sylvis montanus prope. Heidelberg, 1852, W. Zwackh s.n. (H-Nyl. 20416, neotype designated by Meyer 2002).

Description. Life form: lichenized fungus.

[Modified from Aptroot et al. 2009] Thallus crustose, episubstratal, effuse, somewhat shiny, thin, continuous or irregularly rimose, pale gray or gray-green; prothallus white or lacking. Vegetative diaspores absent. Photobiont chlorococcoid alga. Ascomata lecideine apothecia, sessile, 0.3-0.6(-1.2) mm diam.; disk black, epruinose, flat; margin prominent and persistent. Outer exciple dark reddish-brown, inner exciple pale reddish brown to nearly hyaline. Epihymenium hyaline to yellowish or pale reddish brown; hymenium 65-80(-90) µm high, hymenium and hypothecium often with blue-violet granules; hypothecium dark red-brown. Paraphyses ~1.5 µm wide, simple or sparingly branched, tips slightly widened without pigmented caps. Asci 8-spored; ascospores simple, hyaline, ellipsoid, 12-17 × 6-7(-9) µm.

Chemistry. Thallus UV+ white, K-, KC-, C-, PD-; no substances detected by TLC.

Substrate and Habitat. Semi-aquatic on periodically inundated, shaded siliceous rocks.

Distribution. Europe and North America; in North Carolina found in the Blue Ridge ecoregion.

Literature

Aptroot, A., O.L. Gilbert, D.L. Hawksworth & B.J. Coppins. (2009) Lecidea Ach. (1803). Pp. 502-519 in Smith, C.W., A. Aptroot, B.J. Coppins, A. Fletcher, O.L. Gilbert, P.W. James & P.A. Wolseley (eds.). The Lichens of Great Britain and Ireland. The British Lichen Society, London (description as Lecidea ahlesii).

Koerber, G.W. (1860) Ergänzungen zum systema lichenum Germaniae. Parerga Lichenologica 2: 1-501 (original description as Biatora ahlesii).

Meyer, B. (2002) Die Flechtengattung Clauzadea. Sendtera 8: 85-154.