Observation 34857: Peltigera praetextata (Flörke ex Sommerf.) Zopf

Proposed Names

12% (3)
Eye3
Recognized by sight: a dark leafy lichen with very cool details. This one’s for you, Jason!
82% (3)
Eye3 Eyes3
Recognized by sight: rhizines aren’t “soft” looking… maybe

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Eye3 = Observer’s choice
Eyes3 = Current consensus

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Trevor Goward verified a specimen of this
By: Jason Hollinger (jason)
2015-08-26 00:12:09 CEST (+0200)

as Peltigera praetextata, Aug 2015. He kept the specimen at Edgewood Blue.

uh oh!~ another taxonomic Pandora’s box…
By: Debbie Viess (amanitarita)
2010-03-18 04:29:16 CET (+0100)

maybe I’ll just admire them from afar and not delve into the lichen ID, too!

Now we can see what’s going on!
By: Jason Hollinger (jason)
2010-03-18 04:17:09 CET (+0100)

And I’m still confused… So here’s the difference according to the working keys for Ways of Enlichenment:

Peltigera membranacea: lobes wider, no tiny lobules, veins sharply raised, both veins and rhizines with tiny erect hairs, interspaces between veins polygonal or diamond-shaped

Peltigera praetextata: lobes smaller, tiny lobules usually present along stress cracks (check the center of the thallus), veins sharply raised or not, veins often with tiny erect hairs but usually not the rhizines, interspaces between veins lens-shaped

Ernie Brodo doesn’t specifically compare the two taxa, but confirms some of the above, and adds a few things:

P. membranacea: lobes 20-30 mm wide, veins narrow and raised and pale, both veins and rhizines tomentose, surface shiny except for lobe tips

P. praetextata: lobes 7-20 mm wide, veins somewhat raised and light brown, tomentum not mentioned, surface rather dull

I know from personal experience that, despite what Brodo claims, P. praetextata very rarely has crisped margins, and equally rarely has abundant or conspicuous lobules. (It’s easy to tell the two species apart out east, fortunately — we only have one of them here!)

It looks to me like your rhizines are tomentose after all. (The “soft” look I was taught to look for is more apparent in moist specimens, I guess, like in the other photos on MO.) But I also see tiny lobules at the bottom of the first picture.

This is a really tough group that even the the experts have trouble with.

PS. It seems the Kwakiutl tribe on NW BC used these “as a love charm, but it is not clear how (or if) it worked.” :)

I looked at other Peltigera membranacea on MO…
By: Debbie Viess (amanitarita)
2010-03-18 03:35:51 CET (+0100)

and altho the tops are similar, the rhizines are definitely different; for one thing, those in this sighting are rather tough, long and bristly (not jelly-like and smooth).

I did have to look up rhizines, tho (the little projections underneath); like little lichen holdfasts.

BTW, I put up a sharper image; you can see the details clearly now.

tough one
By: Jason Hollinger (jason)
2010-03-17 01:51:26 CET (+0100)

Range of P. membranacea and P. praetextata is same in coastal California, so no help there. Could be either. Wish I knew how to distinguish specimens like this without a microscope…

Created: 2010-03-16 15:52:03 CET (+0100)
Last modified: 2015-03-18 16:44:52 CET (+0100)
Viewed: 327 times, last viewed: 2016-07-09 21:50:35 CEST (+0200)
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