Notes:
Location is upper Morro Creek along Highway 41 West, between Morro Bay and Atascadero.
Habitat is riparian, with a dense canopy of live oak, California bay, sycamore and willow. The specific location is a deep shaded canyon.
Substrate is siliceous non-calcareous boulder situated at or just above the high flood line of the creek. Probably does not become inundated.

Thallus consists of greenish grey convex areoles, K+Y, C-, KC-. Apothecia black, with raised margin lacking algae, margin sometimes pruinose. Hymennium hyaline, hypothecium brown becoming bright brown to orange-brown in K, epihymenium very dark aeruginose, K-.

Spores simple, hyaline, ellipsoid. Average 14.1×7.2µm (13.7×8.0, 16.6×8.7, 14.7×8.4, 13.6×5.3, 12.0×5.7). Ascus stain not done.

Images

Apothecial section at 100x in water
Exciple in K
Apothecial section at 100x in K
POL-

Proposed Names

-57% (1)
Recognized by sight: Non-calciferous rock.
Based on chemical features: K+Y, C-, KC-.
28% (1)
Recognized by sight: Preferred name

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= Observer’s choice
= Current consensus

Comments

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Awesome, thanks
By: J-Dar
2017-02-05 13:38:20 PST (-0800)
The color clearly indicates L. asema
By: Jason Hollinger (jason)
2017-02-05 12:14:01 PST (-0800)

The chemistry of these things is complicated and highly variable. K can be plus or minus easily. The key is whether it has xanthones. But note that L. carpathica supposedly rarely has arthothelin! Ugh. I personally just go with the thallus pigment — if it’s yellowish and coastal then it’s asema, if it’s pure white / grayish and interior then it’s carpathica. If it’s ambiguous… dig deep for that KC+o test or TLC it!

Atranorin absent?
By: J-Dar
2017-02-05 11:54:39 PST (-0800)

Re-tested thallus with K and couldn’t convince myself it was K+Y. Tested under cross-polarized light showed no atranorin crystals in the apothecia.

Yes that’s exactly what I would recommend
By: Jason Hollinger (jason)
2017-01-01 20:44:13 PST (-0800)

This happened to me in eastern Washington. In the field I was excited because this yellowish stuff was clearly different…. Only, it wasn’t. I couldn’t get any positive spot tests. WTF? Then one day I stumbled on the two species growing one on top of the other, and I said “okay, dammit, this is not just environmental variation!” And finally, with much patience, I got a weak C and KC reaction. And TLC eventually vindicated me.

Otherwise, I don’t think there’s a whole lot of difference between L. carpathica and L. asema. :(

I barely got the K+Y
By: J-Dar
2017-01-01 20:14:43 PST (-0800)

the K just burned through the cortex quickly, so adding C didn’t get any reaction. I can try again with a tiny amount of K and add the same for C and see what I get. The thallus is yellow green.

How certain are you this was KC-?
By: Jason Hollinger (jason)
2017-01-01 17:29:15 PST (-0800)

In know colors in photos can be deceiving, but yours are usually so consistent. This sure looks more yellow than typical L. carpathica. Sometimes it can be very difficult to coax good KC+ reactions out of L. asema, especially in shaded locations.