Observation 65492: Xanthomendoza hasseana (Räsänen) Søchting, Kärnefelt & S.Y. Kondr.

When: 2011-04-02

Collection location: Davis, California, USA [Click for map]

Who: Byrain

No specimen available

Growing on living Rhus lancea bark, found on April 2nd when the tree fell of natural causes and I was helping with the clean up. I saved the specimen and branch it was attached to and took pictures today on April 13th since I now have a more powerful camera available.



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Eye3 = Observer’s choice
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By: Byrain
2011-04-15 05:00:10 SAST (+0200)

The identification help is appreciated.

Good enough for me
By: Jason Hollinger (jason)
2011-04-14 22:24:53 SAST (+0200)

No way we’d see hapters at that distance. Must be hasseana/montana. According to the Sonoran Flora (admittedly covering an area a bit south of Davis!) California has X. hasseana and Arizona has X. montana, not even close to overlapping at all. Good thing, otherwise you have to measure the size of the spore septum! :)

(God alone knows why species with wide septum tolerate mediterranean climate better than continental, and vice versa! Only thing I can remember that even begins to bear on the subject is: the reason lichens more frequently have multicellular spores is that they need more genetic material because the spore needs to “hang out” in the sun for a while before the right alga comes along and they can start doing their licheny thing. But how would septum width have any bearing on anything??)

More pics
By: Byrain
2011-04-14 22:00:42 SAST (+0200)

I added two more pictures. I may have pictured some small rhizines in the 4th picture, but I had trouble focusing on it as well as separating the lichen from the bark to get better shots.

Edit: I added a red box around the area with the possible rhizines for ease.

Here are rhizines
By: Jason Hollinger (jason)
2011-04-14 05:43:56 SAST (+0200)

These are pretty well-developed, even for X. hasseana. The “hapters” are trickier. It can take patience to find either for some specimens. A hand lens will help a lot, and a dissecting scope even more!

By: Byrain
2011-04-14 05:33:23 SAST (+0200)

I’ll take more pictures tomorrow trying to show any rhizines.

Edit: I removed my question since I managed to figure it out myself, but Jason answered it anyways and in more depth then I was able to…

Xanthoria s. lato.
By: Jason Hollinger (jason)
2011-04-14 04:42:08 SAST (+0200)

Not quite sure of species. Need to know whether there are “roots” underneath or not. Looks like maybe no, but even then it looks like two species to choose from, X. polycarpa (doesn’t look right) and X. tenax (never heard of it but sounds promising).

Summary of choices:

X. hasseana / X. montana — well-developed rhizines (that is, way longer than the thickness of the rhizine)
X. polycarpa — stubby little “hapters” (that is, peg-like things scarcely longer than they are wide)
X. tenax — lower cortex and rhizines completely missing

Created: 2011-04-14 04:15:35 SAST (+0200)
Last modified: 2011-04-15 04:55:53 SAST (+0200)
Viewed: 77 times, last viewed: 2018-07-20 05:04:36 SAST (+0200)
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