Observation 208060: Melanelixia subargentifera (Nyl.) O. Blanco et al.
When: 2015-06-28
(35.4513° -120.6443° 282m)
Who: J-Dar
Herbarium specimen reported

Notes: Occasional on coast live oak (Quercus agrifolia) in semi-arid open woodland rural site. Does not occur on adjacent deciduous oaks (Q. douglasii and Q. lobata).

Thallus brown, greenish when damp, somewhat rugose, shiny at lobe tips, soralia laminal and marginal (or is that just marginal pseudocyphellae? see photos), isidia possibly intermixed with soredia but hard to tell, no apothecia. Thallus underside pale tan, rhizines simple, concolorous, scattered. Cortical hairs not observed. [EDIT: HAIRS OBSERVED ON THALLUS UPPER SURFACE, SPARSE AND TINY]. Medulla white, C+pinkish and KC+pinkish, barely. Had a hard time getting any reading on the medulla spot test (note photo with no color change), best with freshly exposed tissue and even then the color change is fleeting.

If marginal soralia are not present, this goes pretty well to Melanelixia subaurifera, if they are, then it goes to M. subargentifera.

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Eye3 = Observer’s choice
Eyes3 = Current consensus

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Esslinger confirmed identification
By: J-Dar
2015-12-11 17:33:02 PST (-0800)
Great news!
By: Jason Hollinger (jason)
2015-07-03 14:24:53 PDT (-0700)

On all fronts. Yeah, see what I mean about those “hairs” being impossible to photograph?? They are only one cell wide, extremely minute. But I think you have the right search image now — and if those wee streaks in the focal plane in your image really are hairs, then yours are actually fairly abundant as far as it goes(!)

Dr. Esslinger’s comments
By: J-Dar
2015-07-03 14:13:13 PDT (-0700)

Esslinger looked at this observation and said he would give it 98% confidence as M. subargentifera, cortical hairs on the thallus of course being the dead give away if they are there. I posted a new photo of what I think shows these “hairs”. I hesitate to call them hairs, they are really more like tiny tiny trichomes or something, using the work “hairs” conjures up a lot of images that are nothing like these! Esslinger asked for a specimen, his herbarium representation of this taxa in California is sparse and poor quality.

Maps Maps Maps
By: J-Dar
2015-06-29 11:43:19 PDT (-0700)

I didn’t realize CNALH mapping doesn’t reconcile name changes, or I assume there is a lag time until they catch it, good to know!

Can you email me Esslinger’s contact info? I’d be happy to reach out to him and send specimens if needed.

Thanks!!

I think we need to read those maps carefully…
By: Jason Hollinger (jason)
2015-06-29 09:56:42 PDT (-0700)

Be sure to look at all four CNALH maps! :)

Melanelia subargentifera
Melanelixia subargentifera

Melanelia subaurifera
Melanelixia subaurifera

I’ve recorded both species for southern California in my notes, but the M. subaurifera specimen from Montana de Oro is from 2007, literally only a month or two after I started studying lichens, so while the descsription makes it sound like true M. subaurifera, I’d call it suspect until I can verify it(!)

In general the maps make it clear that M. subaurifera is a more northern species. However, they don’t really make any patterns clear (to me) for central-southern California coast.

I’ll downgrade my vote to “promising”. If this really is a new report for San Luis Obispo, then it should be verified. (Would you be willing to write to Esslinger about this?) And besides, both species appear to be rare in southern California.

Excellent!
By: J-Dar
2015-06-29 09:27:52 PDT (-0700)

Thanks Jason. I looked again this morning and it definitely has marginal soralia, and no true isidia, but I could not find any cortical hairs (lots of lint and stuff and some crazy insect eggs). So it looks to go to M. subargentifera well, my previous hesitation was based on those cortical hairs and lack of specimens in this area on CNALH, check out specimen map, closest is 300 miles away. Two species, M. glabra and M. subaurifera reported from SLO County, neither of which I’ve seen yet.

http://lichenportal.org/...

Good analysis
By: Jason Hollinger (jason)
2015-06-29 08:11:47 PDT (-0700)

Yes, I find the C reaction to be extremely weak in these species, too (Melanelixia subargentifera and M. subaurifera), partly because the medulla is so thin. I can’t imagine how you’d capture the fleeting weak C+ pinkish reaction in a photograph!

The cortical hairs Esslinger’s talking about are extremely minute. Even at 40x and carefully focus-stacking an image I’ve never successfully captured them (to my satisfaction at least). Have you seen M. glabra yet? It’s usually pretty common, and it’s a good one to practice looking for these cortical hairs on. Look especially at the lobe tips. They’re easiest to see when looking parallel to the surface. They should be most abundant on sheltered thalli, I think.

I agree that it looks like your specimens have marginal soralia in addition to the laminal soralia originating on warts/wrinkles. I think this is the more reliable character. M. subaurifera has much finer soredia and (often) true tiny stubby-cylindrical isidia mixed in. M. subargentifera has very coarse almost pustulose soralia, just like you show in these photos, where the soredia themselves are so coarse as to resemble isidioid granules, but never true isidia. If it’s ambiguous whether you have isidia or not, then it’s probably not isidia in this case!

Created: 2015-06-28 18:46:56 PDT (-0700)
Last modified: 2015-12-11 17:32:44 PST (-0800)
Viewed: 72 times, last viewed: 2016-11-13 09:29:20 PST (-0800)
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