Observation 97073: Parmotrema reticulatum (Taylor) M. Choisy

When: 2012-06-09

Collection location: Jamor, Oeiras, Portugal [Click for map]

Who: zaca

No specimen available


Underside of thallus;
Chemical reactions.
C test – repetition.
2012/06/13 – New specimen;
2012/06/13 – New specimen: Chemical reactions.

Proposed Names

58% (1)
Recognized by sight
62% (2)
Eye3 Eyes3
Recognized by sight: with reservations — see comments, especially regarding the odd C test

Please login to propose your own names and vote on existing names.

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
I agree.
By: zaca
2012-06-21 15:15:41 PDT (-0700)
By: Jason Hollinger (jason)
2012-06-20 00:33:33 PDT (-0700)

Clearly we need to start observing our apparently-negative spot tests for 5 hours more often to see if they eventually “change their minds”! :) I’m going to stay with P. reticulatum, despite the very consistently odd C test. I think it’s the best name we can give it.

New specimen; even stranger chemistry.
By: zaca
2012-06-19 14:07:02 PDT (-0700)

I felt a bit curious about the chemical reactions of this species. So, having going back to the place, I found a new specimen at the same tree than the first one and performed the spots test again, but this time I observed for a long time. You can see the result in one of the photos attached: as times goes more intense is the C+ red reaction.

Parmotrema apparently prefers non Mediterranean climate
By: Jason Hollinger (jason)
2012-06-12 11:11:10 PDT (-0700)

It is extremely diverse in tropical America (e.g. Brazil and southeastern USA) These places receive much rain during the warm season. This seems to be a critical factor in determining which flora is present.

Very strange indeed!
By: zaca
2012-06-12 11:00:16 PDT (-0700)

I never heard about any of the species you mention in your message, beyond P. reticulatum.

By: Jason Hollinger (jason)
2012-06-12 10:16:36 PDT (-0700)

Wish I knew who to send this to. This has got to be very unusual.

Double-checking Sipman’s key, I see there are two other related species with other things mixed in with salazinic acid, P. commensuratum and P. pontagrossensis. The first has norlobaridone + variable salazinic; the second salazinic + lichexanthone.

I looked up all the notes I have on things with norlobaridone, and I never noted any sort of C reaction, and the KC reaction is purplish, not reddish. P. ultralucens has lichexanthone in the medulla (it’s almost always in the cortex, not the medulla), but I never once bothered to do a C test on P. ultralucens so I can’t personally confirm that it is C-.

I also can’t find any mention of variability in chemistry of P. reticulata, if anything my sources say it should be only salazinic (most just report the strongest substance, so not so helpful).

Definitely hold on to this thing!

C test
By: zaca
2012-06-12 04:11:52 PDT (-0700)

I repeated the test with C using the old one and the new one. Both gave the same reaction than the previously observed, a bit more intense with the new one. I uploaded a photo with these reactions.

If any genus is going to have weird chemistry…
By: Jason Hollinger (jason)
2012-06-11 15:09:30 PDT (-0700)

Parmotrema is probably it! :)

The funny thing is that …
By: zaca
2012-06-11 15:02:52 PDT (-0700)

the C reagent was brand new. Since you put the question of the bleach I was using not to be in good conditions (I think it was about my observation 96408) I replaced it.
I still have the specimen and I will repeat the chemical tests soon.

I agree, that’s very odd
By: Jason Hollinger (jason)
2012-06-11 14:41:22 PDT (-0700)

This species has very strong salazinic acid. Is it possible your C got slightly contaminated with K by accident one time?? If I had this specimen in the lab, I would definitely verify with fresh reagent. Otherwise, I would be forced to conclude you had an unusual chemical variant with a xanthone or gyrophoric acid mixed with the usual salazinic acid. Only one small problem: in my database of all the secondary substances of all the epiphytic macrolichens occurring in North America, salazinic acid is never once recorded occurring with gyrophoric acid or any xanthones (except lichexanthone in one case but it is C-). I suspect that these are such different chemical pathways that they never mix. Obviously doesn’t mean it can’t, you just need to be that much more absolutely certain of your results!

How to interpret this C reaction?
By: zaca
2012-06-11 12:10:53 PDT (-0700)

It looks a typical Parmotrema reticulatum!

Created: 2012-06-11 12:09:06 PDT (-0700)
Last modified: 2012-06-21 15:15:58 PDT (-0700)
Viewed: 100 times, last viewed: 2017-06-13 00:48:15 PDT (-0700)
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