Observation 203432: Pyxine cocoes (Sw.) Nyl.
When: 2015-04-25
Who: zaca
No herbarium specimen

Notes: Growing on bark.
It took many time to get the genus for these specimens, but at the end I came to the conclusion that it must be Pyxine.
I already found species in this genus, either in rock or on bark, but all had
1) Yellow medulla,
2) Lobes with a “frosen” appearance.
These specimens don’t have any of these features. Let me summarize:
- Thallus clearly bright yellow,
- Lobes narrow, flat except at the margin where are slightly elevated with the tips turned down, appressed to the substact,
- Soredia present, pustulate, disperse (maybe due to youth) mainly at the confluence of lobes and in older part of thallus;
- Lacking isidia and polysidiangia;
- Some black dots spread by the thallus, that can be pycnidia and that I already found in different species of pyxine;
- Underside dark in the middle becoming pale (almost white) at margins, with black, short, strong and furcated rhizines;
- Medulla white;
- Chemistry on thallus and on medulla: C-, K-, KC-.

Pyxine cocoes is known to exist in Azores but doesn’t appear in the checklist for the Iberian Peninsula.

Proposed Names

29% (1)
Eye3 Eyes3
Used references: Thomas Nash III et al. (eds.), Lichen Flora of the greater Sonoran Desert Region, Vol. 1, Arizona State Univ., 2002.

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Yes, it did rain …
By: zaca
2015-04-26 12:26:33 CDT (-0400)

the night before and the weather remained cloudy, so the specimens were not completely dried.

Yes, this looks much more like Pyxine!
By: Jason Hollinger (jason)
2015-04-26 12:18:47 CDT (-0400)

Passing observation: the Pyxine spp. in Florida are well-studied, so I can be confident of my ids, but I notice that the texture of all my specimens of P. cocoes is much more pruinose and dull. Yours are much smoother. I don’t know if that means anything. I do see a few patches of laminal pruina (very typical pattern for Pyxine in general, I wish I knew why it tends to do that instead of producing pruina at the tips like other genera). Maybe it has to do with the conditions, or maybe it rained recently(?)

The only other options for K- sorediate Pyxine in North America are P. subcinerea and P. caesiopruinosa and P. “albovirens”, but all three have yellow to orange and K+ medullas. So they’re out.

Created: 2015-04-26 07:29:54 CDT (-0400)
Last modified: 2015-04-26 07:35:18 CDT (-0400)
Viewed: 24 times, last viewed: 2016-10-26 03:57:29 CDT (-0400)
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