Observation 178175: Caloplaca Th. Fr.

When: 2014-09-13

Collection location: Pogonip Open Space Reserve, Santa Cruz, California, USA [Click for map]

Who: Thomas Laxton (Tao)

No specimen available

The green is old paint that is peeling away from the concrete slab this is lichen was growing on.


Proposed Names

-12% (2)
Recognized by sight
56% (1)
Recognized by sight
31% (2)
Used references: McCune’s Caloplaca of the Pacific Northwest (see comment)

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= Observer’s choice
= Current consensus


Add Comment
Thanks Jason.
By: Thomas Laxton (Tao)
2014-09-14 08:03:36 CDT (-0400)

I have looked at pictures online and Caloplaca holocarpat looks like a close match.

By: Jason Hollinger (jason)
2014-09-14 01:01:36 CDT (-0400)

Using Bruce McCune’s key (it’s on-line somewhere,try googling “Caloplaca of the Pacific Northwest”):

  • on rock
  • non-lobate
  • no soredia or isidia
  • disk clearly yellow-orange
  • the faint yellowish stain around apothecia indicate that the amphithecium must be yellow… certainly not grey or black
  • this would not be considered “seashore”, I think, that applies to immediate coast only
  • thallus lacking or nearly so
  • rock HCl+ / on concrete

Spore septum < ~3µm: C. feracissima (usually on calcareous rock)
Spore septum ~3-4µm: C. vitellinula (usually not on calcareous rock)
Spore septum > 4µm: C. holocarpa (widespread, on both calcareous and noncalcareous rocks)

I’d say the odds are it’s most likely C. holocarpa (s. str.). (It sure looks right. But I don’t know the other two species.)

I’m reluctant to speculate beyond genus
By: Jason Hollinger (jason)
2014-09-14 00:49:47 CDT (-0400)

On concrete, it should be one of the calciphilous species, and this has a very poorly-developed thallus (is there any thallus at all?). So we should be able to narrow it down a lot… But that’s a slippery slope. ;)