Observation 113093: Peltigera canina (L.) Willd.

When: 2012-10-05

Collection location: Mata da Margaraça, Arganil, Portugal [Click for map]

Who: zaca

No specimen available

Proposed Names

19% (2)
Recognized by sight
56% (1)
Recognized by sight

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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OK! Understood.
By: zaca
2012-10-10 13:40:07 PDT (-0700)

Thanks, Jason, for the explanation.

“Margins turned down”
By: Jason Hollinger (jason)
2012-10-10 12:58:48 PDT (-0700)

Yes, just the extreme edge. It’s a hard character to describe, because all Peltigera are broadly concave, but the ones that are “turned down” have these rounded regions at the margins (especially at the lobe tips, not necessarily the lobe axils) that curl abruptly under in the last few millimeters from the edge.

You can see it best on the left side of the second photo (image 271020).

I think it has to do with the relative rates at which the upper and lower surfaces grow. If the upper surface grows faster, then it tends to curl under, if the lower surface grows faster, it tends to curl up. But since the overall shape is concave (it must continue to grow underneath long after the upper cortex stops growing?), in order for it to curl under at the edge, it needs to become scalloped and wavy. This results in the frilly appearance and the axils being erect.

With the phrase
By: zaca
2012-10-10 12:06:31 PDT (-0700)

“the lobe margins are curled under” you mean that only the extremity (margins) of the lobes are curled under, isn’t it?

This might be true P. canina
By: Jason Hollinger (jason)
2012-10-10 11:29:00 PDT (-0700)

The rhizines are woolly and matted, but unlike P. rufescens, the veins are all pale and more importantly, the lobe margins are curled under.

Created: 2012-10-10 11:00:58 PDT (-0700)
Last modified: 2012-10-10 11:29:41 PDT (-0700)
Viewed: 34 times, last viewed: 2017-07-09 14:16:44 PDT (-0700)
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