Observation 117933: Myelochroa aurulenta (Tuck.) Elix & Hale

When: 2012-10-28

Collection location: Kettle Moraine State Forest North, Wisconsin, USA [Click for map]

Who: Andrew Khitsun (Andrew)

Specimen available

Proposed Names

2% (2)
Recognized by sight
-28% (1)
Recognized by sight

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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By: Jason Hollinger (jason)
2012-11-26 17:57:59 PST (-0800)

I don’t know anything with that chemical signature and this appearance! :)

I think, on the balance, this is most consistent with Flavoparmelia caperata - cortex K (greenish once wet) KC+y (yellowish-greenish once wet), medulla K- C- KC very weak.

I don’t know.
By: Andrew Khitsun (Andrew)
2012-11-26 15:40:19 PST (-0800)

I’ve been torturing it for a while. K definitely leaves a stain, on both medula and cortex. Both are greenish (I think it’s normal in the industry to call it yellow, just like nobody ever recognizes that Xanthoria fallax can be green). It seems like the lower layers of medula turn darker, but I think it’s an optical illusion, since it’s just looking dark against the dark underside/substrate. Addition of C doesn’t change the balance much – the color persists if there is not too much C, but gets washed out with larger amounts.
I think I just confused everything out of balance :-(

By: Jason Hollinger (jason)
2012-11-25 22:22:12 PST (-0800)

I think it has to be. It is pustulate, after all, the pustules just usually break down into soredia sooner, and the thallus generally spreads out more. Do the spot tests match? (medulla K- C- KC+ fleeting pink)

Hypotrachyna has pustules like this regularly, but apparently none are known for Wisconsin. You can rule it out easily by checking the rhizines: Hypotrachyna rhizines fork conspicuously and regularly. I’m sure I have a few photos from the Smokies that show this character well. It’s unmistakable.

There’s also Parmelinopsis spumosa and Hypotrachyna showmanii. Both have pustules and the rhizines aren’t so obviously forked. Both are C+ pink/red though from gyrophoric acid. They are small species. (And relatively uncommon.)

Really weird one… Maybe Parmotrema?
By: Andrew Khitsun (Andrew)
2012-11-25 17:35:53 PST (-0800)

Created: 2012-11-25 17:33:19 PST (-0800)
Last modified: 2014-06-21 20:47:06 PDT (-0700)
Viewed: 39 times, last viewed: 2017-06-14 09:13:09 PDT (-0700)
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