I was stumped many times in the past when test didn’t confirm visual ID, or I wouldn’t be able to follow keys because chemical tests didn’t check out. Now I can guess where my problem was – I tended to choose flatter, outer parts of thallus to tease out and expose medula, because there I didn’t have to dig through all the isidia-soredia-and-whatever-else-might-be-in-the-middle-of-the-thallus. That approach now seems unwise, but I just didn’t know better at the time.

I tend to try to test where the medulla is thickest anyway, but now we know it’s doubly-important. Thanks for following up on that.

It’s all the same species, but basically, the thin parts of lichen, with thin layer of medula, don’t respond to C at all, even if they have fairly developed soredia, but towards the center of thallus I have not just pink, but red forming instantaneously when touched by C.

Yes it was a beautiful specimen. As usual. It’s just not fair. I get a few scraggly lobes barely hanging on for dear life here in so. Cal. and I count myself blessed! Haha, and to think this guy Hasse (lichenologist here turn of the century ~1900) would describe species based on these scraps! Many have never been seen again. The real miracle, is they’re mostly holding up after all these decades and vast sea-changes in methodology and taxonomy. What a guy. Yeah, me, I just like to look at purty flowers…

You know, I don’t have that much experience with this yet – I’m at the level of a blacksmith, but need to become a clockmaster. I’m going through this batch trying to make sure I’m dealing with the same species, not two mixed together (the patch of lichen was very expansive, and it’s not that unusual for me to pick more than one species not realizing it). Then I’ll torture them some more to see what’s going on here.

Good to get it right once in a while. :) Interesting that it was testing negative even under some soralia, usually that’s where the secondary substances are strongest if anything. Tricky little devil.

After another specimen from a location nearby tested strongly C+, I thought it was different species (see bottom two photos I just added). But I returned to the original specimen and re-tested it – sure enought there is plenty of pink there. The only problem is – some parts test negative. I guess not all medula is created equal.

that your C has “expired”. It’s happened to everyone. Bleach out-gasses really fast, and can go flat within days or weeks depending on how it’s stored. I’m sure you know all that, but it’s worth a reminder just in case!

Regardless of the C test, I still argue that P. missouriensis is the most promising name for this thing.

K test leaves some stain on the cortex, whether you call it yellow or green. But C test is definitely negative: I tried on lobe tissue and under soredia – it’s all the same.

P. missouriensis is the only one that looks anything like this. I guess the lecanoric acid is just really weak?? Chemical deficient strains must exist for all these things, I suppose, just like there are albino humans, deer, etc.

I must have picked a wrong genus – Punctelia. It doesn’t check out. Lower surface is white. Abundant soredia looks like soredia on the lobe tips, and like isidia in the center (or isidia looks like soredia?). K-, C-.