Observation 108891: Porpidia flavocaerulescens (Hornem.) Hertel & A.J. Schwab

Posting this because the more I look at several common orange crusts (Lecidea lapicida and others, Porpidea flavocaerulescens and others, Rhizocarpon oederi, and Tremolechia atrata – I’ll post some examples of these) the more they confuse me. Wasn’t even convinced this was a Porpidia until ink mount (see photo) revealed perispore, as some other features could have led to a different interpretation.

Going over references again I’m wondering if this might be P. flavocruenta (apo sectons bled reddish in K). I’ll go ahead and post this and get back after some more consideration (or suggestions from Jason).


Looks like Porpidia-type ascus structure, but could just be paraphyses behind. Wasn’t doing very well with this – guess I should do a squash next time.
ink mount
ink mount

Proposed Names

55% (1)
Eye3 Eyes3
Used references: Brodo, Irwin M., Sharnoff, Sylvia Duran and Sharnoff, Stephen (2001) Lichens of North America; Thomson, J.W. (1997) American Arctic Lichens (which seems confusing, perhaps some changes since 1997), 2. The Microlichens; Smith, C.W., Aptroot, A., Coppins, B.J., Fletcher, A., Gilbert, O.L., James, P.W. and Wolseley, P.A. (2009) The Lichens of Great Britain and Ireland
Based on microscopic features: hymenium approx 100u; paraphyses approx 1.5u diameter with apex aprox 3u and pigmented, found it very difficult to determine degree of branching (very conglutinate) – took a while to find some branching and anastomosing; spores 8/ascus average 18×9u
Based on chemical features: medulla iodine negetive, apo section bled reddish

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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Thanks for the advice
By: Jason Hollinger (jason)
2012-09-07 12:43:02 CDT (-0500)

Good to know that K messes it up.

plain old india ink
By: Richard Droker (wanderflechten)
2012-09-07 09:20:29 CDT (-0500)

Yes. Didn’t work at first and realized that K might dissolve gelatinous perispore. Anyway it worked in H2O keeping distance between slide and cover glass small.

I’ve got no clue!
By: Jason Hollinger (jason)
2012-09-06 13:13:57 CDT (-0500)

But I’m blown away by how striking the “halo” is around spores in ink mount. Did you use a bottle of just plain old india ink?

Created: 2012-09-06 10:58:05 CDT (-0500)
Last modified: 2012-09-06 10:58:06 CDT (-0500)
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