When: 2014-04-25

Collection location: Matinha de Queluz, Sintra, Portugal [Click for map]

Who: zaca

No specimen available

Every time I think of this species can not avoid a half-hearted smile. The fact is that it was always in front of me, not only at this location but in several others, whenever there exist trees with a thick bark, like Quercus suber. Now I can understand better the observation in the British Flora after the description: “On dry bark of tree trunks, especially Acer and Quercus, often dominating the side of the tree, …”. Indeed, it is present at most of old trees at this location, though most of the times one can not see the apothecia, but only the white tallus that covers a great ammount of a side of the trees. Performing the C test there one gets consistently C+ red.
Average dimension of the spores:
Me = 14.2 × 5.8 um ; Qe = 2.5 (N=36).


Chemical reactions;
Microscopy: Asci and spores – 1;
Microscopy: Asci and spores – 2.
Host: Quercus suber, with a very thick bark;

Proposed Names

87% (1)
Used references: British Flora: Smith et al. (Eds.), The Lichens of Great Britain and Ireland, Bristish Lichen Society, 2nd ed., 2009.
Based on microscopic features
Based on chemical features

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= Observer’s choice
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Add Comment
Well you definitely found spores this time!
By: Jason Hollinger (jason)
2014-09-14 00:48:02 CDT (-0400)

And how. Beautiful microscopy. This Arthonia pruinata is very considerate, giving you this handy C test to verify your id!