Observation 116494: Pleopsidium chlorophanum (Wahlenb.) Zopf

When: 2012-09-07

Collection location: Roche A Cri State Park, Wisconsin, USA [Click for map]

Who: Andrew Khitsun (Andrew)

No specimen available

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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It just means adding india ink under the coverslip
By: Jason Hollinger (jason)
2012-11-12 17:27:55 CST (-0500)

Here’s R. Droker’s images: see last two photos in observation 108891.

ah, yes
By: Danny Newman (myxomop)
2012-11-12 17:12:30 CST (-0500)

I’m now noticing the difference in the presence/absence of those black apotheicia. that looks like one of the best up-front distinguishing characteristics.

what’s an ink mount?? I’d google it, but your answers are like a siren’s call to lichen island. :)

Aha! That, I can answer!
By: Jason Hollinger (jason)
2012-11-12 16:05:53 CST (-0500)

Rhizocarpon consists of alternating tiles of black (apothecia) and yellow (thallus), with a distinctive thin black background (prothallus). Acarospora and Pleopsidium both are made up entirely of yellow areoles (thallus) with the apothecia (typically mild-colored) immersed inside these areoles. Microscopically they are completely different, Acarospora and Pleopsidium have numerous tiny hyaline simple spores stuffing each ascus, while Rhizocarpon has larger spores either hyaline or brown, and either septate to full-on muriform. Rhizocarpon spores also have a thick soft gelatinous perispore which shows up on an ink mount as a clear, diffuse halo. (R. Droker posted an excellent photo of this phenomenon.)

how to distinguish
By: Danny Newman (myxomop)
2012-11-12 15:30:32 CST (-0500)

between this and Rhizocarpon (asks the lichenologically-challenged mushroom person)?

I’m not sure this is going to help…
By: Jason Hollinger (jason)
2012-11-12 15:14:24 CST (-0500)

Sonoran flora distinguishes Pleopsidium flavum from P. chlorophanum thus:

“1. Discs convex, orange-yellow, 1-3 mm across . . . P. chlorophanum
2. Discs plane to convex, yellow, apothecia less than 5/8 mm across . . . P. flavum

P. chlorophanum differs from P. flavum in having a smooth, smaller squamulose thallus, and larger apothecia… P. chlorophanum is a rare, alpine species in Europe… P. flavum is a Mediterranean species… with a broader ecological amplitude. It is assumed P. chlorophanum occurs in North America at high elevations, but so far we have seen only one specimen from North America [from Channel Islands in southern California]."


On bluff faces – usually hard to get,
By: Andrew Khitsun (Andrew)
2012-11-12 13:12:45 CST (-0500)

but sometimes strays to where the photo can be taken. I’d call it P. chlorophanum for now, since the species is fairly common and is also listed in the Adams County where this park is located. P. flavum is possible too, but I don’t know much about that one at this point.

Created: 2012-11-12 13:04:18 CST (-0500)
Last modified: 2012-11-12 13:07:58 CST (-0500)
Viewed: 47 times, last viewed: 2017-06-14 10:34:51 CDT (-0400)
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