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.” :)
