Observation 224870: Lecanora Ach.

When: 2015-12-07

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

Who: J-Dar

Specimen available

Tree of Heaven (Ailanthus altissima) trunk bark at old homestead dating to 40’s or 50’s, in a semi-arid grassland setting.

Thallus white, thin, K+Y, prothallus not seen. Soredia absent. Apothecia cinnamon brown with distinct white thalline margin.

Something close to Lecanora allophana? Micro to come.


Different Lecanora on left, maybe L. circumborealis.

Proposed Names

57% (1)
Recognized by sight
28% (1)
Recognized by sight
28% (1)
Recognized by sight

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= Current consensus


Add Comment
I’ll keep collecting and posting
By: J-Dar
2017-07-07 21:28:49 PDT (-0700)

until we get a good L. pacifica. Just gotta keep carving out the hours in the day to do the workups.

Ah yes, one of “those”
By: Jason Hollinger (jason)
2017-07-07 19:35:13 PDT (-0700)

What exactly do they mean by “smooth thallus”? Such a subjective character. But probably obvious once you’ve seen a handful of good typical reference specimens of each species. It would be awesome if you could document L. pacifica on MO. It should be common in your area, as you say. You know what would be amazing? Find that magical “rosetta stone” specimen in which the two species are growing side-by-side! Something to look forward to, ha!

(Also don’t forget that L. chlarotera itself is beset with morphological variation and problems. I think some authors split off particularly verrucose specimens as L. subrugosa.)

By: J-Dar
2017-07-07 19:07:57 PDT (-0700)

Based on range, Lecanora pacifica is more likely. The key character I can’t get past easily is the amphithecial crystal solubility in K. These were quite distinctly entirely soluble (see photo collage). But admittedly I’m new to this test and reading the results, so I very well could have missed something. I also don’t know what Nash considers “gray tinge” for pacifica, when most of the online photos show pretty bright orange-brown epruinose apothecia.

I would guess L. chlarotera or L. rugosella
By: Jason Hollinger (jason)
2015-12-10 08:31:07 PST (-0800)

It’s all going to depend on the type of granules / crystals in the epihymenium. If the epihymenium is really dark it can be very hard to see the granules, but hopefully yours will not be so dark. That usually only happens when the apothecia are black.