Acolium sessile

Taxon

Acolium sessile

Authority
(Pers.) Arnold (1885)
Synonyms
Cyphelium sessile
BLS Number
1545
General Description

Lichenicolous on Pertusaria coccodes, more rarely P. amara and P. albescens on trunks of old oaks, which are typically open and well lit, and is commensalistic to mildly pathogenic. Local. S. & E. British Isles. 

A. sessile causes considerable modification of the host thallus; it is usually darker in colour and the production of isidia and soredia of the host is partly suppressed. Specimens of A. inquinans on bark have larger apothecia and ascospores. For differences from A. marcianum, also parasitic on Pertusaria, see A. marcianum.  

Distribution Map
Key to map date classes