Observation 319880: Caloplaca Th. Fr.

When: 2018-05-25

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

34.4767°N 119.9988°W 216m [Click for map]

Who: J-Dar

Specimen available
Collection number: Jason Dart 1025

Notes:
On smooth trunk bark of Quercus agrifolia in a coastal oak woodland setting, about a mile from the ocean.

Thallus verruculose, white, K-, C-, pycnidia common with dark orange shiny ostioles. Apothecia orange, small 0.5-0.8mm, adnate, plane to somewhat flexuous, never convex, disk finely roughened (pruina?), proper margin dominant, often curling inward and pulling the whitish grey thalline margin over. Disk and proper margin K+R, C-, thalline margin K-.

Spores hyaline, polarilocular, 8/ascus. Average size 12.1×6.0, Isthmus 3.9µm (n=12).

Spores are just too small for C. stanfordensis so I’m going with a tentative C. pyracea.

Images

Proposed Names

57% (1)
Recognized by sight
28% (1)
Based on microscopic features: Spore size

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= Observer’s choice
= Current consensus

Comments

Add Comment
I agree with you
By: Jason Hollinger (jason)
2018-06-28 00:42:42 CDT (-0500)

In the Great Basin, our material clusters nicely. So I’ve been creating herbarium names for our cerina group and atroalba group. I could describe several species based on our material. But… there’s a lot of work comparing our material to material from elsewhere before that can happen. And I’ll bet anything the circumscriptions which work so well in the Great Basin fall apart elsewhere. I don’t know what to do with it all. But it feels good to understand the local material well enough that I can at least give them working names.

One good thing that comes out of the exercise is a good understand, or at least better understanding, of what “true” pyracea, cerina, atroalba, etc. is. And that’s where I justify my comment that this doesn’t look like “true” pyracea. I still have no idea what true stanfordensis and these other sp. N look like. But still, having a few fixed points helps tremendously in understanding the vast “sensu lato” variation we see outside the regions in which these taxa were originally described.

Let’s call it Caloplaca,
By: J-Dar
2018-06-28 00:32:46 CDT (-0500)

call it good, and tuck these into the herbarium for someone else!

I guess my only thing is that I want to understand the difference between the taxa we have and be able to distinguish them. Here’s to the next collection!

My understanding, based on rumor mostly…
By: Jason Hollinger (jason)
2018-06-28 00:12:58 CDT (-0500)

is that a number of PhD students have embarked on various small-scale revisions, but that the problems continue to be intractable, even with modern molecular techniques. I believe one worker at least has found multiple genomes within a single thallus, for example. Apparently there is something very strange going on, genetically, with Caloplaca. At least that’s my take away message.

With other life forms, e.g., plants, they can count chromosomes and do all sorts of controlled experiments. (Not to mention there being way more funding and botanists! :) We lichenologists, on the other hand, know embarrassingly little about really fundamental things like sex and resynthesis. If we don’t actually know how lichens are reproducing, how can we expect to interpret sequences correctly? We just wave our hands and hope for the best, relying still very heavily on congruence with morphology and chemistry (thank god!) to confirm molecular hypotheses.

So, yeah, Caloplaca continues to elude us, even after a decade or two of intensive effort from a huge diversity of researchers with increasingly sophisticated tools.

So more than 10 years later and with plenty of specimens
By: J-Dar
2018-06-27 23:55:21 CDT (-0500)

no one has named these? Seems odd, but maybe Caloplaca just isn’t very inviting for PhD students! So atroalba too? I don’t see that one here. And spore isthmus measurement is not clear for me either, I posted one pic of my measurement lines, I kind of just averaged the width-wise end of the locule down the lengthwise center of the spore.

Consider my hands thrown in the air!
By: Jason Hollinger (jason)
2018-06-27 23:50:23 CDT (-0500)

I look forward to what if anything various researchers make of these difficult Caloplaca groups — holocarpa group, cerina group, atroalba group, etc. etc. (The latter two are the ones that really kick my butt in the interior. We don’t have many holocarpa group.)

Sorry, I’m working through these and posting in real time
By: J-Dar
2018-06-27 23:36:52 CDT (-0500)

I probably should get everything in order and THEN post, to save the future onlookers the pain of figuring out my process! Yes its McCune’s 2012 Caloplaca Key that separates stanfordensis based on larger spores (15-17µm length). Who to trust? I have no idea! This specimen keys fine to stanfordensis in Wetmore’s treatment in Nash V3, but since pyracea wasn’t dealt with at that time, I was looking to other newer sources. Arup doesn’t seem to deal with the holocarpa group in western NA except his 2007 treatment of cerina…Oh man, since neither pyracea nor stanfordensis were treated in this paper I rather ignored it, but sp. 1 is based on Ross 226 from San Luis Obispo, and looks a lot like my other posts with the abundant dark orange pycnidia! This one didn’t have those distinctive pycnidia in the sample I collected. I guess this will be an evolving situation. What was your comment, throw your hands up in the air?

I remember you talking about this before…
By: Jason Hollinger (jason)
2018-06-27 23:01:50 CDT (-0500)

My notes have C. stanfordensis with, if anything, shorter spores than C. pyracea. I realize there is some variation in the literature. Which source(s) are you trusting? For example, your spores are right in the middle of the range reported by the Sonoran Flora for C. stanfordensis. (Your septum is slightly narrower, but I find that my septum measurements are almost universally smaller by a small percentage than the literature in every case. I must be measuring it wrong. Whatever, I guess, so long as my measurement is consistently off, I can convert confidently, ha!)

Created: 2018-06-16 16:21:21 CDT (-0500)
Last modified: 2018-06-29 00:08:02 CDT (-0500)
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