Observation 97162: Pertusaria DC.

When: 2012-06-09

Collection location: Estádio Nacional, Oeiras, Portugal [Click for map]

Who: zaca

No specimen available

A sterile specimen, growing on bark, with all chemical reactions negative.


Close up;
Chemical reactions.
Chemical reactions on medulla, 4 days after.

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Bad news for Pertusaria “velata” at least
By: Jason Hollinger (jason)
2012-06-13 17:59:20 CDT (-0400)

We should, I suppose, consider the possibility this isn’t even a Pertusaria. Not that I can suggest better alternatives. But there are very few Pertusaria with no chemistry. (Who know what P and UV would turn up, though.)

Bad news?
By: zaca
2012-06-13 17:19:40 CDT (-0400)

I returned to the site od the observation and “rediscover the same specimen”. I was even able to see the result of the tests made 4 days ago (see thenew photo attached). I performed the new spot tests on medulla and I have to say these were not according what was expected. In fact, the C reaction was negative and the K and KC reactions were very weak yellow. I uploaded a photo with these reaction. In order to avoid mistakes I performed the spot test again in other palece in the same specimen and also in a new specimen that I found nearby. All these reactions were the same.

There seems to be a catch…
By: Jason Hollinger (jason)
2012-06-13 01:32:12 CDT (-0400)

Pertusaria velata should never be sorediate! There is P. hemisphaerica and Ochrolechia antillarum, but neither look right (smooth/thin not strongly verrucose like this). Still. It would be interesting to see if yours was also C+ red inside like mine. I’m clueless.

Very nice, Jason.
By: zaca
2012-06-12 20:33:47 CDT (-0400)

That is really very close. I can only notice a small change in colour, mine is whitish, yours greyish. Even some very small dots (what are they? being too small for ostioles) are present in both specimens. I only hope to find the specimen again and do the appropriate spot tests. According to the Sipman’s key is “rare in western and central Europe” and, the bad new is that, it has “usually a single reddish disc”.
Many thanks, Jason.

Picky, picky, picky
By: Jason Hollinger (jason)
2012-06-12 19:42:49 CDT (-0400)

You’re right, it’s P. trachythallina which has thamnolic. I apparently just remember P. velata having a very strong spot test (lecanoric acid is very strong). See these photos:

20110524-9, Smokies
20101219-199, central Florida
20101219-200, central Florida

I noted in the latter two, that the cortex was apparently C-, but the medulla was C+ red. Note the soralia are virtually invisible. It was a joke originally, but now, I really wonder. Maybe this is what you have…

By: zaca
2012-06-12 18:31:46 CDT (-0400)

CNALH says:“Spot tests: K-, C+ red, KC-, P-, UV-”.

Sure looks like P. velata
By: Jason Hollinger (jason)
2012-06-12 17:50:59 CDT (-0400)

But there’s no way to miss the K+y of thamnolic acid!! British Flora has no non-sorediate species on bark with K- C- KC-.

Created: 2012-06-12 16:43:41 CDT (-0400)
Last modified: 2012-06-12 16:43:43 CDT (-0400)
Viewed: 80 times, last viewed: 2017-06-13 03:54:54 CDT (-0400)
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