Northwest Lichenologists

puzzling foliose

  • 23 Apr 2017 11:21 AM
    Message # 4770895

    Hi all,

    I have a puzzling little foliose lichen. It grows on volcanic rock in juniper and sage steppe around 4700 feet elevation. This thallus is only 12mm across, is K- and what look like apothecia may not be apos. The lower cortex is light tan with white rhizines. It is not working out in the keys for me. Any suggestions? Pictures in the photo gallery are labeled LABE-444.


  • 05 May 2017 9:37 AM
    Reply # 4816569 on 4770895

    Been anticipating definitive answer, so just mention my 1st impression of something like Endocarpon, however that's pyrenocarpous.

    Last modified: 05 May 2017 1:21 PM | Richard Droker
  • 05 May 2017 5:24 PM
    Reply # 4817272 on 4770895

    What I have so far is: Esslinger suggested Psora californica, however Knudsen thinks it's a Placidium. I need to find more if this so I have more to work with, all I have now is the small sample that is in the picture.

  • 06 May 2017 8:14 PM
    Reply # 4818643 on 4770895

    Maybe Miriquidica scotopholis.  Commonly found on basalt.    See 

  • 07 May 2017 7:49 AM
    Reply # 4819038 on 4770895
    Bruce McCune (Administrator)

    I like the suggestion that this is a Psora species. You can confirm/refute this by a K test of an apothecial section under compound scope. If Psora, the epithecium will be K+ red. Also, if Psora the lower surface should not have true rhizines but can have hyaline rhizohyphae.

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