Observation 85338: Lichen P. Micheli

When: 2011-12-28

Collection location: Stebbins Cold Canyon Reserve, Solano Co., California, USA [Click for map]

Who: Byrain

No specimen available

Growing in a dry riverbed, same location as observation 81622, different rock.

About the chemistry, would the greenish K reaction be considered K-? It also appears to be C-, KC brought out orange/red (Better seen in person) which turned greenish/yellow after a minute or so, and I noticed in the picture that CK brought out a little yellow. Am I interpreting this correctly?

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Lichens are very patient
By: Jason Hollinger (jason)
2011-12-29 23:59:45 EST (-0500)

One advantage of lichenology: it is so easy to preserve specimens!

rock art.
By: Debbie Viess (amanitarita)
2011-12-29 20:58:26 EST (-0500)
By: Byrain
2011-12-29 20:54:44 EST (-0500)

This location seems to have numerous interesting lichens and your brush suggestion sounds like it could work well while I wait to be able to try with a toothpick under a dissecting microscope, I’ll try it next time. As for the K+y, I didn’t notice it till looking at the pictures, though I will be sure to wait for a color change if I see K+y again.

I collected a few apothecia, I can look for spores, but I doubt I could get a good apothecial section without more magnification first. Unless I don’t need one I’d prefer to wait so I don’t waste what I collected.

Gorgeous specimen and photos!
By: Jason Hollinger (jason)
2011-12-29 20:41:28 EST (-0500)

Spot tests can be difficult to diagnose. I think the problem here is the thallus is so thin that the K is dissolving it completely and the “greenish” color we’re seeing is the algae and/or the underlying substrate. My recommendation is to try to use less reagent. The ideal technique is to brush a very tiny amount (much less than one drop) on with a toothpick or capillary tube while watching through a dissecting microscope. This gives the most controlled conditions and most reliable results. In the field, you may still get acceptable results by applying with a toothpick or small brush, maybe, instead of an eyedropper. Also, be sure to give the KOH time to turn orange or red if you see a K+y test.

All that said, I agree that there seems to be at least some sort of yellowish/orangish thing going on here. The overall “look and feel” strikes me as a Buellia (should have gray/brown spores with two cells each). That genus has many species with norstictic acid (K+y to orange and/or red). Some other genera you would have to rule out microscopically to be thorough are: Lecidea, Porpidia, Rhizicarpon, in decreasing order of likelihood.

Created: 2011-12-29 19:48:42 EST (-0500)
Last modified: 2011-12-29 20:47:33 EST (-0500)
Viewed: 53 times, last viewed: 2017-06-10 07:39:55 EDT (-0400)
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