Observation 322024: Lecidea Ach.

When: 2018-04-28

Collection location: South Yuba River State Park, Nevada Co., California, USA [Click for map]

Who: Pgrunow

No specimen available

On large boulders and cliffs along canyon wall. It made large patches in a few locations. The specimens I noticed were all out of the Yuba River’s spray zone, but it could be that there were some down at the river’s edge. There are quite a few different rock types/layers here, and it is a good lichen spot. Unfortunately, I am not completely sure which one is pictured/don’t remember.
All specimens were on large rocks, so there are no micro data.
Crustose with a distinct, thick grayish-black prothallus in many places, but not completely continuous. The small, rounded areoles (or squamules?) are invariably reddish with a wavy, lobed and upturned margin. This margin has a whitish-gray perimeter that appears to be pruinose.
Apothecia are black, large, with black rims that are almost always taller and “pinched” in appearance.


Proposed Names

29% (1)
Recognized by sight: thallus and/or prothallus eliminate L. mannii, fuscoatra, pacifica, paddensis, kingmanii, et al. L. atrobrunnea sensu stricto does not have the scales shaped as noted, but maybe some species going under that name do? While very similar, I can’t find pictures for L. cascadensis with an obvious dark prothallus like this. Truckeei is similar, but also unlikely; chemistry may be needed to eliminate. While scaly, it does not look like Psora to me. Perhaps this is Miriquidica, the only species here of which is M. scotopholis. From what I can tell, though, that species has scales overlapping more frequently than this (giving it a visibly lumpier surface), but maybe chemistry or microscopy would be needed to tell. Another possibility is Rhizocarpon bolanderi, but it seems that the scale center is generally uplifted in R. bolanderi, opposite of here.
Used references: California Lichens, California Lichen checklist, Lichen Portal, iNaturalist, Desert Lichens of Reno (Herre, 1911), Images of British Lichens, Keys to the Lichens of North America (Brodo)
Based on chemical features: Bleach: no reaction (in situ)
29% (1)
Recognized by sight: see above; after reviewing pictures, there are a few sections where the scales are overlapping and the surface is somewhat lumpy, so it may well be Miriquidica, unless someone can recognize it is not.
Used references: see above
29% (1)
Recognized by sight: suggested by Jason in comment
Used references: see below

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= Observer’s choice
= Current consensus


Add Comment
Hard group
By: Jason Hollinger (jason)
2018-08-05 08:13:20 PDT (-0700)

Another to keep in mind in this region is Rhizocarpon bolanderi. Side-by-side it is usually distinguishable because it is distinctly smaller than the Lecidea atrobrunnea group. In the alpine there are even more options: Immersaria and Calvitimela, for example(!) This is a very popular phenotype for whatever reason.

Created: 2018-07-05 14:36:48 PDT (-0700)
Last modified: 2018-08-12 19:10:20 PDT (-0700)
Viewed: 55 times, last viewed: 2019-03-16 22:04:18 PDT (-0700)
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