Observation 165056: Arthonia ilicina Taylor

When: 2014-03-28

Collection location: Sintra, Portugal [Click for map]

Who: zaca

No specimen available

This observation together with observation 165505 and observation 165507 are devoted to a group of crustose lichens growing on a branch of a shrub. This is my first attempt to consider a set of lichens growing together for the purpose of classification. I attached several photos of this group and include one with numbers to distinguish between them (4th photo). They have all different features and at first sight one can immediately say that:
I – Is a Graphidaceae, probably a Graphis or Phaeographis, the latter being more probable, due to the form of apothecia with open discs;
II – Resembles very clearly an Arthonia sp.. Which one? Only microscopy can help.
III – Is somewhat related in appearance to the genus Buellia, if one can confirm that the fruitbodies are apothecia, which is not clear due to their reduced dimensions.

This observation is devoted to the lichen marked as II. As said above it resembles an Arthonia and the microscopy reenforces that initial thought. Surprinsingly the ascospores, being several sepate (5-septa) colourless when young and brown when mature as in many species of Arthonia, are one of the biggest found in this genus and only one species in the British Flora presents such values: A. ilicina. The rest of the features of this specimen are in accordance with the description given in the reference.


The three lichens under consideration;
The three lichens under consideration;
The three lichens under consideration;
Chemical reactions;
II – Microscopy: Asci;
II – Microscopy: Spores.

Proposed Names

58% (1)
Recognized by sight
Used references: Ref. (British Flora): Smith et al. (Editors), The Lichens of Great Britain and Ireland, Bristish Lichen Society, 2nd edition, 2009.
Based on microscopic features
Based on chemical features

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= Observer’s choice
= Current consensus


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Created: 2014-05-11 18:20:19 CDT (-0400)
Last modified: 2014-05-11 19:09:27 CDT (-0400)
Viewed: 36 times, last viewed: 2019-07-13 02:24:07 CDT (-0400)
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