Images of British Lichens
Arthonia varians (Davies) Nyl.
Lacks a thallus or its own photobiont (and arguably a "lichen" only as a member of a generally lichenised genus), occurs in the hymenium of Lecanora rupicola, taking over and blackening the apothecia, retarding their development. Ascospores (1-)2-3-septate (compare A. apotheciorum). Widespread and evidently common where the host occurs, but evidently under-recorded.
Refs: Smith et al. (2009), 170; Purvis et al. (1992), 87; Dobson (2005), 70 (photo); Dobson (2011), 76 (photo).
Also claimed to be the cause of the blackening commonly seen in apothecia of Lecanora sulphurea, according to Whelan (2011), but there seems to be no agreement on this and I have not so far found this to be the case myself.
|In apothecia of Lecanora rupicola on stonework of old bridge, Kindrogan, Perthshire, March 2008|
|In apothecia of Lecanora rupicola (apothecia scarcely pruinose) on coastal rocks, St Martin's Haven, Pembrokeshire, May 2009|
Lichens HOME PAGE | Index of Species | Conditions of Use and e-mail contact | References | Site Home Page
© A.J. Silverside
Uploaded November 2008, last updated January 2016