Observation 71198: Arthonia caesia (Flotow) Körber
When: 2011-07-02
No herbarium specimen

Proposed Names

39% (2)
Recognized by sight
70% (1)
Recognized by sight: Yes, you are right… A. caesia! The hazy whitish blue color of the apothecia is from pruina, so depending on the amount of pruina they can range from almost white all the way to black… but they’re mostly what I like to think of as “baby blue.” One of my all time favorite lichens!

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Please compare
By: Andrew Khitsun (Andrew)
2011-08-02 19:51:26 CST (-0600)

Please compare with observation #73081, guys. That was also on White Pine, but wet after rain and colors were juicier, with lots of green.

Arthonia caesia?
By: Andrew Khitsun (Andrew)
2011-07-27 17:39:07 CST (-0600)

I wonder if it is Arthonia caesia. I’ve come across the observation by Chris Parrish (34995) and found it somewhat similar. Not a single description in the books mentions pine as a host tree (lots of other species though).

These are pretty common.
By: Andrew Khitsun (Andrew)
2011-07-26 21:23:27 CST (-0600)

I got some samples, so the testing is in order.

Ambiguous thallus
By: Jason Hollinger (jason)
2011-07-26 21:12:23 CST (-0600)

I confess that I haven’t paid much attention to the bewildering terminology used for the various textures of thallus yet. It could be called granular, isidioid, verruculose, and many other things. They could even be true soredia or isidia. Someone showed me an isidiate Rinodina once that looked anything but isidiate to me. It all seems a big mess to me still.

But this I am willing to say with some degree of certainty: you’ll find algae and fungal hyphae in whatever that green stuff is. Maybe cortex, maybe not. So I’d say it’s definitely “thallus” in the broadest sense, not prothallus.

well put
By: Andrew Khitsun (Andrew)
2011-07-26 20:32:12 CST (-0600)

I can’t agree more about apothecia. What about thallus? Or is it prothallus? I mean all that green stuff scattered around and almost totally missing in other places (soredia?, algae?).

not familiar with this
By: Jason Hollinger (jason)
2011-07-25 22:43:23 CST (-0600)

The apothecia can’t seem to decide whether they are black, black with whitish pruina, or out-and-out pale gray. May be Micarea?

There are a few crustose species which can grow on flaky pine bark, but not many, and you’ll typically find them in the cracks between bark plates. It’s one of those things where you really need a lichenologist to show them to you, then you’ll start seeing them all over. You would have to grow really fast to make it on the outer surface of red pine bark, I imagine.

On trunks too.
By: Andrew Khitsun (Andrew)
2011-07-09 20:20:21 CST (-0600)

OK, just wanted to make some corrections to the previous statement. These lichen do grow on trunks too (see bottom photo). Except, usually pretty high up the tree where bark is smooth – that’s why I didn’t notice it right away. Perhaps, the reason it doesn’t grow on red pines (Pinus resinosa) is the latter doesn’t have any smooth bark. If anyone wants to debunk this myth of mine – please go ahead.

White Pine
By: Andrew Khitsun (Andrew)
2011-07-08 22:56:04 CST (-0600)

These lichen are growing on white pines (Pinus strobus) – only on branches, it seems, since I couldn’t find them on trunks. Every white pine in our development has these lichen, but not the red pines that grow side-by-side with them.

Created: 2011-07-08 21:45:17 CST (-0600)
Last modified: 2011-07-30 22:02:37 CST (-0600)
Viewed: 114 times, last viewed: 2016-10-23 13:18:25 CST (-0600)
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