Observation 32364: Parmelia squarrosa Hale

When: 2010-01-21

Collection location: North Falmouth, Falmouth, Massachusetts, USA [Click for map]

Who: Nathan Wilson (nathan)

Specimen available

Notes:
Growing on a fallen birch branch in my front yard.

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Proposed Names

-12% (2)
Recognized by sight
62% (2)
Recognized by sight
28% (1)
Recognized by sight

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Comments

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By: Jason Hollinger (jason)
2010-01-23 09:11:42 PST (-0800)

I can’t decide. It has the squared-off lobe tips of Parmelia, but it has predominantly raised, dot-like pseudocyphellae like Punctelia.

You can also see red stains on the bits of dead thallus where the cortex has been scraped off — that’s probably from the secondary chemistry — norstictic acid? in Parmelia (K+r), lecanoric acid? in Punctelia (C+/KC+r). Is it more likely that nature would be performing a K test on these exposed bits of medulla than C followed by K?? If something even just slightly basic drips on it, you’ll see the (very strong) K+r reaction easily.

Short of chemistry, best way to distinguish these two species — the isidia make it either Punctelia rudecta or Parmelia squarrosa I believe (Parmelia saxatilis is only on rock?) — is to check the rhizines. They should be clearly squarrose or bottle-brush-like in Parmelia squarrosa, simple in all Punctelia spp.

Created: 2010-01-21 19:39:08 PST (-0800)
Last modified: 2010-01-21 19:39:08 PST (-0800)
Viewed: 51 times, last viewed: 2019-02-01 14:58:22 PST (-0800)
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