Observation 65179: Physcia leptalea (Ach.) DC.
When: 2011-04-02
Who: zaca
No herbarium specimen

Proposed Names

-29% (1)
Used references: irish lichens
Based on chemical features
58% (1)
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Recognized by sight

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Comments

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I’d go with P. leptalea based on that info, too
By: Jason Hollinger (jason)
2011-04-10 13:37:44 PDT (-0700)

Neither are species I’m familiar with (though both occur in southwestern USA where I’ve studied a fair bit).

PS. Interesting that irishlichens.ie calls the white mottling “pseudocyphellae”. Most of my sources call that feature “maculae” instead. The former is supposed to be caused by cracks in the cortex, presumably facilitating gas exchange into the medulla. (I’ve heard it said that gas-exchange through the cortex is like trying to breath through a plastic bag!) The latter is caused simply by small areas of medulla which lack algae, thus appearing white from above, but the cortex itself is continuous and unbroken. It’s thought that such a feature would allow more light into the interior of the medulla, I think, possibly an adaptation to high light conditions. (Too much light can cause photosynthesis to break down, ironically, I forget what the technical term for this is. Quenching, maybe?) I’ll have to take a closer look at the next white-spotted Physcia I run across!

You are absolutely right,
By: zaca
2011-04-10 11:44:54 PDT (-0700)

I chose the wrong species. I checked Heterodermia and I found nothing similar. But within Physcia you already pointed out the possibilities: P. leptalea and P. tenella. Clearly they are good candidates for this specimen. The problem is to choose correctly. Let´s see (always according to “irish lichens”), both have the K-reaction of my specimen, both have pseudocyphellae (said to be small in the second species), both have long cilia (said to be proeminent in the first species), both are fertile with dark apothecia (with thick, swollen margins, discs often +/- pruinose in the first species). In addition, in the second species the lobes are +/- erect and presents cream coloured soralia, which is absent in the other. With all this, my best choice is P. leptalea. What do you think?

Not with those cilia!
By: Jason Hollinger (jason)
2011-04-10 09:01:41 PDT (-0700)

I’d look at Heterodermia (I’d have suggested H. erinacea, for example, but maybe it’s not present in Portugal?), or maybe more likely, Physcia leptalea or P. tenella (both are shown on irishlichens.ie). I don’t remember the difference between those two Physcia. Aren’t one or both supposed to be sorediate? (Doesn’t preclude presence of apothecia, though, for sure.)

Created: 2011-04-04 17:38:55 PDT (-0700)
Last modified: 2011-04-11 13:12:04 PDT (-0700)
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