Observation 212505: Caloplaca Th. Fr.

When: 2015-08-05

Collection location: Santa Barbara Co., California, USA [Click for map]


Who: J-Dar

Specimen available

On Quercus agrifolia branch tip in old coast live oak woodland within a mile of the ocean, at the western end of the Transverse Range.

Thallus distinctly all white, K- [EDIT: I was able to get K+Y distinctly but not in older thallus material], C-, tiny orange dots are apothecial initials, prothallus absent. Apothecia with white thalline margin, K-, proper margin K+R, same color as disk, which is K+R also [EDIT: See last photo added for K+R reaction], apothecia often growing together. Apothecia with algal cells in thalline margin, discontinuous along bottom.

NOTE: Apothecia color is more dark orange than the dissecting microscope photos show (maybe it was a little wet?), it is not scarlet or blood red. See UPDATED PHOTO at bottom for best color rendition of apothecia disk.

In Nash’s Sonoran flora for Caloplaca, this keys to C. sp. 3 if you consider the thallus to be well developed and light grey with no orange. If you consider it not well developed or with some orange places then you get to C. stanfordensis or C. holocarpa group.


Finger scale :)
Apothecia cross-section showing traces of K+R on the disk (tested before x-section cut), algal cells in margin and discontinuous at base.
UPDATED PHOTO. Apothecia detail showing strong K+R. The top cluster of apothecia shows purplish red color after several minutes, the bottom right apothecia is fresh K with bright blood red reaction.
Fresh K test
Week old K test
Asci in apothecial section

Proposed Names

76% (2)
Eye3 Eyes3
Used references: Nash Sonoran Flora, Lichenportal.org
-76% (2)
Recognized by sight
-76% (2)
Recognized by sight: Sphaerophorin and/or isosphaeric acid for H. persoonii, or placodiolic acid for other options…
-76% (2)
Recognized by sight: Thallus not yellow and K-. Apothecia of specimen probably not red enough and too small.
-84% (1)
Recognized by sight

Please login to propose your own names and vote on existing names.

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Microscopy in action: One mistery solved.
By: zaca
2015-09-15 16:11:13 PDT (-0700)

These are weird spores for Caloplaca. I could not find anything similar in the British Flora (where, however, only the spores of 10 species are represented).

No question about it
By: Jason Hollinger (jason)
2015-09-15 15:02:06 PDT (-0700)

Definitely Caloplaca. Thank you for sticking to your story! :)

Let this specimen join the vast ranks of undescribed species of Caloplaca. Hooray!

Microscopy Added!!
By: J-Dar
2015-09-15 13:36:12 PDT (-0700)

Finally got a scope, and had a couple of hours to play with it this week, and of course this had to be my first specimen to review. Using the scope and getting the photo’s was the easy part, making sense of what I was seeing is the difficult part! It seems to me that these spores are clearly polarilocular, which puts us at Caloplaca. The Nash species 3, to which it keys, is a subset of the C. holocarpa group.

I don’t have any spore measurements at this time, still need time to get that part all figured out. If there is anything else you would want to see photos of, let me know.

I don’t always trust my own spot tests!
By: Jason Hollinger (jason)
2015-08-25 14:19:37 PDT (-0700)

They can be very misleading. But if you retested it with my objections specifically in mind and still saw a distinct K+ red/violet reaction, then I’m forced to accept it, however improbable are the conclusions it leads us to.

Of course, once you get that microscope (!) you’ll be able to distinguish between the proposed genera trivially. The polarlocular of Caloplaca are unmistakable, as are the acicular spores of Haematomma and Ophioparma.

Clearly, this specimen is worth waiting for. I hope this story isn’t finished. :)

I don’t know if you should straight up trust my spot test reading…
By: J-Dar
2015-08-25 14:09:46 PDT (-0700)

I ran the K test several times, the disk immediately turns immediately dark red with K, but if it is possible or likely that it is just bleeding color from the pigments rather than showing a chemical change, based on your experience, we should consider that. I added a couple new photos.

Okay, I’ll have to trust your reading of the spot tests
By: Jason Hollinger (jason)
2015-08-25 09:44:23 PDT (-0700)

I can’t wait to find out what this thing is. I think we’ve just about ruled out all the known species from your area. Very exciting!

Whether or not it shows in photos
By: J-Dar
2015-08-18 17:28:48 PDT (-0700)

the apothecia disk is strongly K+R turning slightly purplish with time. Thalline margin is K-, except for a few random uncommon reddish spots.

Yes, K+r strong would rule out Lecanora
By: Jason Hollinger (jason)
2015-08-15 10:58:45 PDT (-0700)

But I’m just going off of what I see in the photos of the apothecium section with K under dissecting scope. That doesn’t look strong to me. Is it possible the already red color is just darkening in K? I think the lack of “bleeding” around the apothecium section on the slide is more telling.

But… it’s so hard to be sure about spot tests without actually seeing it in person. So much can go wrong or be ambiguous or whatever. It’s frustrating sometimes to see observations like this that just don’t add up and the key point of contention is a screwy spot test…

Well it’s 2 cents I didn’t have before!
By: J-Dar
2015-08-15 09:43:27 PDT (-0700)

I’ll double check K+R, my notes say strongly K+R on the apothecia disk, is that what you would doubt for Lecanora?

This is not going to be popular but…
By: Jason Hollinger (jason)
2015-08-14 21:32:44 PDT (-0700)

This doesn’t look truly K+r to me. I think it’s more likely you have a Lecanora. Both Ophioparma and Haematomma should be distinctly K+ violet or blue in section, and I mean extremely strong. (And you are way out of range for either.) Caloplaca s.l. is hard to rule out conclusively without seeing if the spores are septate — there are just so many strange Caloplaca that don’t look anything like the typical cheerful orange jobbies. Admittedly this looks more orange/red than typical for Lecanora, but there are some that can look this bright. Check in the subfusca group in particular, probably one of the ones without granules/crystals in the epihymenium. Unfortunately, I’m worried that, without a microscope and polarizing filters, we might not be able to get any farther than speculation. :(

That’s my two cents, at least.

I´m not familiar with the genus Haematomma and
By: zaca
2015-08-12 13:01:00 PDT (-0700)

in fact, I only recently found a species in this genus, but that was sorediate. However, both the thallus and the apothecia seems wrong for Caloplaca. The scarlate apothecia with a white rim made me think of Haematomma. That’s the best I can guess about your specimen and I don’t know I to test the lichen substances of Haematomma spp..

I believe you are absolutely correct, Zaca
By: J-Dar
2015-08-11 22:53:28 PDT (-0700)

I’ve never even heard of Haemotomma, interestingly spot tests are similar to Caloplaca, so when I got that K+R I never turned back from the Caloplaca key. I can’t get anywhere in the Haemotomma key unless you know how to test for the acids, as indicated in the comment above. In CNALH there aren’t any records near here for the genus, on the mainland at least (2 specimens from Santa Cruz Island unidentified to species), unless there is an old name that hasn’t been updated on their specimens.

A few Lecanora species also look similar…

Seems more like Haematomma to me.
By: zaca
2015-08-11 17:07:12 PDT (-0700)

Did you consider it?

Created: 2015-08-11 16:19:14 PDT (-0700)
Last modified: 2015-09-15 15:03:05 PDT (-0700)
Viewed: 167 times, last viewed: 2018-02-06 12:18:20 PST (-0800)
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