Observation 103418: Pertusaria amarescens Nyl.

When: 2012-07-28

Collection location: Monte de S. Bartolomeu, Nazaré, Portugal [Click for map]

Who: zaca

No specimen available

The main difference to the specimen in observation 103417 is that this one lacks soralia.

Proposed Names

29% (1)
Based on chemical features
58% (1)
Eye3 Eyes3
Used references: See the comments.

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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Congratulations on finally getting the British Flora!
By: Jason Hollinger (jason)
2012-07-31 14:33:31 -05 (-0500)

I’m sure you will find it helpful.

Jason, your clinical eye is impressive.
By: zaca
2012-07-31 14:05:17 -05 (-0500)

I think that you are right, since besisdes the slightly difference in chemistry there are also differences in the thickness/wartness of the thallus and in the dimensions of soralia of the two specimens (this one and the one in observation 103417), as you mentioned.
Finally, I received the British Flora. So, now I can see the details there.

British Flora shows two similar species
By: Jason Hollinger (jason)
2012-07-31 01:02:47 -05 (-0500)

P. amarescens – thallus thin, minutely cracked-areolate, grey to ±yellow-gray in patches; soralia 0.1-0.3 mm, fleck-like, pale grey-white; K+y, C+o, KC+o, P+o/r
P. flavicans – thallus thick, smooth to coarsely warted-areolate, yellow- or green-grey; soralia 0.3-0.8 mm, ±rounded, pale yellow-green; K-, C+o, KC+o, P-

Both occur in macaronesia, on rocks. In the description for P. amarescens it describes it as “Like P. flavicans but thallus pale primrose-yellow to dull olive-grey, much thinner and more delicately rimose-cracked…” It also has stictic ± norstictic acid in addition to the thiophanic acid that P. flavicans has (the source of the yellowish coloration, also UV+ orange).

You may well have both species. This specimen looks distinctly K+ yellow, what do you think? (The other is a bit ambiguous.)

Created: 2012-07-30 17:59:50 -05 (-0500)
Last modified: 2012-08-02 18:10:41 -05 (-0500)
Viewed: 69 times, last viewed: 2017-06-13 09:55:26 -05 (-0500)
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