Observation 235452: Lichen P. Micheli

Notes:
Physconia (isidiigera)?

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That’s possible
By: James Bailey (Silversea_Starsong)
2016-04-01 11:21:22 PDT (-0700)

I actually see quite a lot of these “ring” lichens. More so than I see normal ones.

Yes, definitely some sort of damage in the middle
By: Jason Hollinger (jason)
2016-03-29 07:51:51 PDT (-0700)

Maybe it almost died during a drought or because of a fire? But the growing margins held on, and now you get this ring. The new growth is probably still too young to produce apothecia. Or it’s just still struggling.

Thanks Jason!
By: James Bailey (Silversea_Starsong)
2016-03-27 17:27:35 PDT (-0700)

So here’s my main question then, how has it formed like this? It seems that Parmelina coleae is the sort that forms from the middle and creates a large patch. But this one has clearly formed a sort of ring and left a gap/darkened area in the center. Do you think it formed normally and slowly degraded from the inside to the outside?

We might still consider Xanthoparmelia, by the way
By: Jason Hollinger (jason)
2016-03-27 11:29:22 PDT (-0700)

I know it doesn’t look greenish/yellowish, but sometimes in the shade on cloudless days the colors can be very misleading, and sometimes Xanthoparmelia can be remarkably gray. (I think most species have both atranorin and usnic acid in the cortex?)

Of course the lobe shape still looks wrong.

Also, I forgot to suggest Parmotrema, but I think we can all agree that the lobes are too small and closely-attached for that genus.

Sorry, this doesn’t look like Physconia to me
By: Jason Hollinger (jason)
2016-03-27 11:26:21 PDT (-0700)

The lobe shape — broadly rounded tips — and “shiny” texture (compared to the very distinctly dull, usually strongly pruinose texture of Physconia) convince me that this is a “parmelioid” genus. But which? It’s gray, so that rules out Flavoparmelia and Flavopunctelia. It’s got no dots or cracks so Punctelia and Parmelia are out. There are a few eastern genera (Myelochroa, Canoparmelia) that we can safely ignore. There aren’t many options left! But I would still personally prefer to see the C+ red verification before I rule out the possibility that I’m just forgetting something.

First thing that strikes me about Parmelina
By: James Bailey (Silversea_Starsong)
2016-03-27 10:10:15 PDT (-0700)

is how papery the lobes look, don’t think mine has that plus its kind of Physconia looking. But I know far less than you do Jason.

Not really enough to go on
By: Jason Hollinger (jason)
2016-03-27 01:20:02 PDT (-0700)

But if you got a really strong C+ red reaction off of the medulla, I think you could be confident that this is Parmelina coleae anyway.