Observation 198867: Physcia adscendens (Fr.) H. Olivier
When: 2015-02-15
(35.4514° -120.6437° 280m)
Who: J-Dar
No herbarium specimen

Notes: Uncommon on bark of dead fruitless mulberry. Small round thallus, just over 1cm diameter, with abundant upturned lobes, greyish white with some whitish scaly pruina, upper cortex K+Y, medulla white, looks K+Y but is supposed to be K-, so maybe thallus bled into it? Underside white to slightly pale brownish in middle of thallus.
Long black rhizine-like hairs protruding from lobe tips, some pointing directly up, and small black rhizine-like hairs on upper surface of some lobes, but uncommon. Rhizines on underside white, simple, well-spaced.
Soredia marginal, often with expanded hoods, but not always.


Thallus upper cortex K+Y
Exposed medulla in center of photo should be K- for this species

Proposed Names

61% (2)
Eye3 Eyes3
Used references: Nash and Brodo
Based on chemical features: Upper cortex K+Y

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Good example of difficulty of K test on medulla in Physcia
By: Jason Hollinger (jason)
2015-02-18 20:23:32 CET (+0100)

It can be extremely difficult to apply K to just the medulla without touching the cortex at all.

Created: 2015-02-16 01:15:19 CET (+0100)
Last modified: 2015-02-18 20:20:27 CET (+0100)
Viewed: 25 times, last viewed: 2017-02-20 07:44:24 CET (+0100)
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