When: 2017-11-28

Collection location: Monterey Co., California, USA [Click for map]

35.8075°N 120.3109°W 445m [Click for map]

Who: J-Dar

Specimen available

On siliceous rock, often on moss over rock. Loosely adnate. Fertile.


Lobe tip upper surface pruina
Medulla K+Y

Proposed Names

1% (2)
Recognized by sight
-46% (2)
Recognized by sight: Densely pruinose on lobe upper surface.
61% (2)
Recognized by sight: Thallus is maculate, medulla is K+Y
-56% (1)
Recognized by sight

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= Observer’s choice
= Current consensus


Add Comment
This whole group is confusing to me
By: Jason Hollinger (jason)
2017-12-07 12:24:25 CST (-0600)

All those species are so variable and blend together so much. Sorry. :(

Probably very old
By: J-Dar
2017-12-07 08:03:37 CST (-0600)

I just looked at the lobe tip pruina and guessed P. biziana before looking at chemistry. Then I noticed it was subtly but distinctly maculate. I don’t know P. phaea well, is there something odd looking for the gestalt? This was from an intruded bedrock outcropping, and the lichen community was very well developed and very old. These Physcia thallii were loose, often sprawling over top of the moss, making me wonder was it the chicken or the egg first? Did the moss lift up the lichen, or did the lichen crawl over the moss?

By: Jason Hollinger (jason)
2017-12-06 12:19:55 CST (-0600)

Sorry, got my medulla K tests backwards. :)

Ignore P. biziana and P. albinea. The only other one you need to consider is rare saxicolous specimens of P. aipolia. But I agree with you on this. Wow. I never would have guessed P. phaea on this one.