Observation 267574: Xanthoria (Fr.) Th. Fr.

When: 2017-01-17

Collection location: Don Edwards San Francisco Bay NWR, Fremont, California, USA [Click for map]

Who: Pgrunow

No specimen available

On posts near headquarters parking lot. These will be a pollution-tolerant species that grows near the bay. I can describe some of the habitat nearby if it helps.


Proposed Names

28% (1)
Recognized by sight
-29% (1)
Recognized by sight
31% (2)
Recognized by sight: More likely on wood

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= Observer’s choice
= Current consensus


Add Comment
Since this is not on rock,
By: Pgrunow
2017-02-26 13:38:16 CST (+0800)

I would think it is not xanthoria elegans.
The thallus is not very lobed either, if I am looking at it correctly.
The thallus appearance and substrate suggest X.candelaria to me, but the underside is apparently dark, as shown in the photo. This would have an enormous amount of apothecia for that species as well.

Sorry, still hard to say
By: Jason Hollinger (jason)
2017-02-26 12:30:30 CST (+0800)

Some specimens one just needs to see personally. This is just a difficult one, I guess.

Photo of the underside added
By: Pgrunow
2017-02-26 12:11:56 CST (+0800)

It did not peel off the substrate nicely, it was difficult to take off the surface. Just crumbled eventually, getting stuck under fingernails. So is that directly attached to the substrate?

Fixing a typo
By: Jason Hollinger (jason)
2017-02-06 09:29:19 CST (+0800)

J-Dar meant to say lower cortex lacking goes to Caloplaca:

Xanthoria — fully corticate below, either X. elegans or X. parietina (strange form for either, I’d say)

Caloplaca — fully attached to substrate or detaching near tips and corticate below only at margins and tips

Caloplaca or Xanthoria
By: J-Dar
2017-01-19 22:56:16 CST (+0800)

Others might know just by seeing the pics, but to confirm you can check whether it has a cortex on the underside, if lacking then it goes to Xanthoria, which might have some cortex under the lobe tips, but not throughout the underside.