Observation 64582: Lichen P. Micheli
When: 2011-03-20
Herbarium specimen reported

Notes: All micrographs mounted in 5% KOH solution.

Images

137903
137900
137901
137902
137904
138197
100x
138198
100x
138199
400x
138200
400x
138201
400x
138202
400x
138203
1000x, 10.92 micrometer divisions
138204
1000x, 10.92 micrometer divisions
138205
1000x, 10.92 micrometer divisions

Proposed Names

75% (2)
Eye3 Eyes3
Recognized by sight

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Eye3 = Observer’s choice
Eyes3 = Current consensus

Comments

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Great work!
By: Jason Hollinger (jason)
2011-03-26 10:13:16 CDT (-0400)

We can definitely rule out Lecidea because of the brown epihymenium and easily-separated paraphyses. I don’t have my literature with me, remind me in a week if I haven’t commented again. You found one of the common and very annoying problems with rock-dwelling crustose lichens: for some reason they produce very scant quantities of spores. I’m not sure there are any in any of these photos (maybe a few on the left of the second 1000x photo? maybe one of the asci in one of the 1000x photos has spores in it? or is that paraphyses showing through?) It can be maddeningly difficult to scour “acres” of squash prep like these to find just one or two sometimes. Still, if we assume simple spores, this might be enough to go on. I need to check the keys, I just don’t remember the other options at the moment. Rhizocarpon is, at any rate, looking more promising. (Incidentally, the “smoking gun” for Rhizocarpon is an indistinct halo around the spores in an india ink prep. That, and a distinctive ascus structure as seen with very high-quality scope and lugol’s solution stain. But I’ve never succeeded in seeing either, even with specimens of certain id.)

Looks like one of the Rhizocarpon concentrica look-alikes again
By: Jason Hollinger (jason)
2011-03-22 12:41:39 CDT (-0400)

But I’m personally unwilling to officially propose that name without microscopy! :)

Created: 2011-03-22 01:50:38 CDT (-0400)
Last modified: 2011-03-24 13:10:27 CDT (-0400)
Viewed: 97 times, last viewed: 2016-10-23 19:28:29 CDT (-0400)
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