Observation 64151: Arthonia punctiformis Ach.
When: 2010-04-03
No herbarium specimen
0 Sequences

Proposed Names

11% (2)
Recognized by sight: Note the black dots (puncta)
29% (1)
Recognized by sight
86% (1)
Eye3 Eyes3
Recognized by sight

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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Testing & Microscopy
By: Andrew Khitsun (Andrew)
2011-07-27 20:16:49 PDT (-0700)

I understand that with such a featurless species testing is a must.

Arthonia seems likely to me, too
By: Jason Hollinger (jason)
2011-07-27 19:06:06 PDT (-0700)

I haven’t seen nearly enough to even guess at a species, though.

Like Arthonia quintaria.
By: Andrew Khitsun (Andrew)
2011-07-27 16:48:08 PDT (-0700)

It looks somewhat like Arthonia quintaria – not a WI species. It must be something close. With more than a dozen species of Arthonia in WI, most are not illustrated at all. Very common around here, so I’ll keep obtaining specimen for testing.

Might be
By: Andrew Khitsun (Andrew)
2011-03-15 19:36:24 PDT (-0700)

I was thinking along those lines. Although I don’t think it’s Phlyctis argena, there are some other lichens that look just like patch on the tree (or rock), and you can’t see “normal” lichen features without microscope. On the other hand, it might actually be P.argena. The problem is, all the pictures I’m finding are looking different – and I actually have pics matching “typical” P.argena from the field guides. The white patches I have here (and the other observations I mention below) are very common around where i live, but I can’t find anything similar in the guides I have or online.

It could be a lichen
By: Jason Hollinger (jason)
2011-03-15 19:17:19 PDT (-0700)

There is something called the “whitewash lichen”, Phlyctis argentea, I think. These have always completely stumped me in the past. I’ve never found spores, conidia, soredia, or anything on them.

still in doubt
By: Andrew Khitsun (Andrew)
2011-03-11 21:43:44 PST (-0800)

I still think it’s a lichen. I’ve looked up Biscogniauxia atropunctata, and it looks totally different everywhere, more like my other observation of B.atropunctata (#64115). In addition, I posted few more observations similar to this one (#64287 & # 64288). All of them are characterized by the rounded patch shape typical for lichens, not the long, wound-like shape of B.atropunctata. Also, note that the latter looks like it eats into the fabric of the tree and is surrounded by the unaffected bark, while lichens are comfortably resting on top of the bark.
I’d greatly appreciate if you could link to any images that look similar

Thank you Michael!
By: Martin Livezey (MLivezey)
2011-03-09 09:47:01 PST (-0800)

The link is very helpful.

Not a lichen
By: Michael Wood (mykoweb)
2011-03-09 09:03:25 PST (-0800)

Biscogniauxia atropunctata is not a lichen, but it is in the Xylariaceae, related to Xylaria and Hypoxylon. See the "Home of the Xylariacae: for info:


Foresters call it “hypoxylon oak canker”.

By: Andrew Khitsun (Andrew)
2011-03-08 20:26:12 PST (-0800)

I don’t know if posting lichens on MO is OK.

Created: 2011-03-07 16:36:02 PST (-0800)
Last modified: 2013-11-25 05:11:50 PST (-0800)
Viewed: 146 times, last viewed: 2017-06-08 16:01:35 PDT (-0700)
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