Observation 204954: Lecanora muralis (Schreber) Rabenh.
When: 2015-05-23
(34.446° -119.7049° 149m)
Who: J-Dar
No herbarium specimen

Notes: On sandstone boulders in open sunny aspects with surrounding coast live oak (Quercus agrifolia). Uncommon. Occurs with Xanthoparmelia species and other crusts. Thallus K-, KC+Y (weakly), C-. Apothecia with algal cells in margins, discs light brown, margins distinctly white rimmed.

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Eye3 = Observer’s choice
Eyes3 = Current consensus

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Here’s an example of what it should look like
By: Jason Hollinger (jason)
2015-05-25 18:46:57 CDT (-0400)

observation 12025

This is a very reliable character.

No kidding!
By: J-Dar
2015-05-25 18:01:30 CDT (-0400)

I took a few leaps of faith in the Sonora Flora keys, but really had no confidence that it wasn’t a different species. I’ll have to look for the discontinuous algal layer, that’s a good tip!

Difficult group
By: Jason Hollinger (jason)
2015-05-25 17:52:27 CDT (-0400)

But I find most specimens can be identified fairly confidently, surprisingly. (No thanks to the keys in the literature!)

L. muralis s. str. is distinctive in being one of the only ones with a discontinuous algal layer, interrupted by irregular conical bundles of hyphae plunging down from the cortex. It also has fairly “flat” lobes like this. Colors tend to be muted greenish-bluish-yellowish-brownish, also like this. It’s the most common one on the coast by far.

In the Sonoran Flora you have to call this a hollow medulla in order to get to the right name, and that’s just ridiculous. There are some species with very inflated-looking lobes that could be called “hollow”, but this one in particular is anything but hollow.

Bruce Ryan’s key is probably the best — he was, after all, the expert on the group in the southwest. But it’s probably worth cross-checking species descriptions against the ones in the Sonoran Flora. (The descriptions there are pretty good, and are probably based on Ryan’s work, and almost certainly incorporate newer observations than the last version of the key in his unpublished work.)

Created: 2015-05-25 13:35:37 CDT (-0400)
Last modified: 2015-05-25 17:42:58 CDT (-0400)
Viewed: 43 times, last viewed: 2015-10-05 03:57:35 CDT (-0400)
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