Observation 199953: Acarospora thelococcoides (Nyl.) Zahlbr.
When: 2015-02-26
(35.4003° -120.2796° 686m)
Who: J-Dar
No herbarium specimen

Notes: On red clay soil at edge of grassy meadow and chaparral slope.
Thallus aereolate, tan/buff, +/-discontinuous, mostly occupied by apothecia and barely visible.
Apothecia abundant, aspicilioid, 1-3 per aereole, mostly less than 1mm but occasionally up to 1.5mm, “volcano-like” with a small depressed black disc surrounded by a thickened margin covered in crusty white pruina. Cortex remnants persistent on side of apothecia after it emerges, giving the apothecia a crenate appearance.
Cross-section photo shows the thalline (lecanorine) margin with algal layer.
Further ID requires micro.

Aspicilia contorta photo at CNALH look the closest (http://lichenportal.org/...), and the apothecia is described by Nash as looking like small volcanos when the thalline margin is elevated. It occurs on calcareous rock and there is one record in the region.
Or it could go to Lecanora…

Species Lists


Apothecia x-section
Apothecia x-section detail, showing algal layer in thalline margin

Proposed Names

28% (1)
Used references: Nash and Brodo keys and descriptions

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Aw, shucks
By: Jason Hollinger (jason)
2015-03-04 01:19:18 EST (-0500)
Kudos to Mr. Hollinger
By: J-Dar
2015-03-04 01:07:21 EST (-0500)

His unfailing detailed comments have brought this and many many more observations to a higher level of identification confidence. Citizen science can only go so far without true professional input…

this is an exemplary observation
By: Danny Newman (myxomop)
2015-03-03 20:38:02 EST (-0500)

whether or not I am too lichenologically challenged to comment further. bravo.

There are some Aspicilia which grow on soil…
By: Jason Hollinger (jason)
2015-03-01 12:37:24 EST (-0500)

But I agree with you, this Acarospora thelococcoides looks promising.

I think it’s best to see “squamule” as a specialized type of “areole”, one which lifts at the edge and clearly has a lower surface. Your (excellent!) cross-section photos clearly show that these areoles are fully-adnate. The full variation, in order of degrees of adnation, might be:

gomphate (Kerry uses this term a lot in Acarospora)

The term “verrucose” here must refer to the degree of convexity. I would personally call these “strongly convex” not verrucose, perhaps even “bullate”. But note how cracked they are, and that gives the surface an uneven irregular texture which could be called “verrucose”, I guess.

Neat that this species is particularly considered an indicator of healthy soil crust communities. But regardless the species, anything this well-developed on soil is going to indicate a good undisturbed community(!) Gorgeous specimen.

By: J-Dar
2015-03-01 11:50:20 EST (-0500)

A. thelococcoides is described as an indicator of undisturbed soil habitats, often occurring with other rare species (lichens and otherwise). This location is a very sensitive and undisturbed spot with natural vernal pools, very rare endemic plants, and many other lichens on the ground.

I like Acarospora
By: J-Dar
2015-03-01 11:48:10 EST (-0500)

And A. thelococcoides looks really good. Aspicilia was a wild guess, some features seemed to fit, others like occurring on soil, did not. What I described as cortex remnants persistent on apothecia are described under A. thelococcoides as large pruina flakes. Is there anything in the photos that you can point to that fit “verruculose” for the thallus? One apothecia per squamule would fit also, with the Nash caveat that it sometimes looks like more than one while in the process of asexual division of thallus. What’s the difference between squamule and areole in this context?

By: Jason Hollinger (jason)
2015-03-01 00:47:43 EST (-0500)

Diploschistes is out. But consider, for example, Acarospora thelococcoides (there’s a photo in the Sonoran Flora if you have a copy, vol 3). My primary concern is the thallus is composed of far too regular dispersed well-developed areoles. Aspicilia, even when dispersed as in A. contorta, is never so “neat”. But… you’ve clearly got something I’ve never seen, whatever genus it belongs to! :)

Gotta get that compound scope
By: J-Dar
2015-03-01 00:35:29 EST (-0500)

Crusts probably aren’t worth my time without it! This one is C-, K- and KC-, which I think excludes Diploschistes.

Did you consider Diploschistes, too?
By: Jason Hollinger (jason)
2015-02-28 18:19:23 EST (-0500)

I think D. diacapsis is common on soil. But there are also a couple Aspicilia on soil, too. Could even potentially be an Acarospora. Spores will immediately distinguish between these.

Created: 2015-02-28 13:28:49 EST (-0500)
Last modified: 2015-03-03 04:44:39 EST (-0500)
Viewed: 182 times, last viewed: 2017-07-22 03:58:50 EDT (-0400)
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