Observation 209419: Physcia adscendens (Fr.) H. Olivier

When: 2015-07-06

Collection location: Santa Barbara Co., California, USA [Click for map]

34.4201° -119.7429° 30m

Who: J-Dar

No specimen available

Collected from a landscape tree, probably carob, in a residential area adjacent to live oak and riparian habitats.

Thallus small, <1cm, with ascending narrow white maculate lobes, <1mm wide, with marginal cilia 1mm or less, bicolored, white at base dark above, lower surface without cortex and soredia covering underside of lobe tips, soredia white to green, rhizines long and white or translucent. Thallus K+Y, medulla white, K-.

Nash Sonoran Flora key doesn’t have P. tenella, instead keys to P. tenellula, not much readily available info on this species. Brodo lichens of NA key goes to P. tenella, and is the only description that mentions maculae on lobes, which is distinct on this specimen. Both species reported from this County.

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Add Comment
By: J-Dar
2015-07-11 19:50:55 PDT (-0700)

But not quite!

There is one photo on-line now
By: Jason Hollinger (jason)
2015-07-11 19:26:31 PDT (-0700)


Click on the image, then “open medium-sized image”. You can almost see it. ;)

By: J-Dar
2015-07-11 19:02:14 PDT (-0700)

Nash Sonoran Flora says "P. adscendens differs from P. tenellula in several aspects. “The latter is much smaller and has a different type of soralia and hairs on the upper surface.” So, maybe we can figure out what that means some day!

This definitely has more stubby lobes than photos for P. tenella, and unfortunately nothing close to resembling “hoods”. Esslinger offered his help with Physiaceae determinations, so maybe I’ll collect some more samples and send them to him when I get that Melanelixia subargentifera in the mail.

90 miles north of this collection, in San Luis Obispo County, P. adscendens fits the descriptions well, with classic hood shaped soralia.

I should probably keep my mouth shut…
By: Jason Hollinger (jason)
2015-07-11 11:24:29 PDT (-0700)

The Physcia adscendens group is extremely variable in southern California.

I’m finally comfortable with P. tenella from northern states. And even around Monterey, California it looked well-behaved. This “typical” tenella has very long, narrow (relative to length), delicate, “spidery” lobes. (Whereas typical adscendens has short, stubby, broad lobes.)

Of course the keys stress the inflated hoods of adcendens. And, yes, these are common, at least in typical, well-developed specimens. But when young, both species will lack soredia, or worse, adscendens will start to form soredia in some cases before the hood is obvious.

This is where southern California comes in. Down there adscendens goes crazy. It will produce such abundant soredia that the hoods will often “turn inside out” making them match the description of tenella. And every conceivable variation and combination of the various extreme forms are common. (Sometimes all mixed up together on the same tree!)

So I have concluded tentatively that P. tenella doesn’t occur in southern California.

But what about this P. tenellula???

PS. I see maculae in adscendens frequently. Actually, now that I look at my photos, almost every specimen.

Created: 2015-07-09 21:28:14 PDT (-0700)
Last modified: 2015-07-11 11:25:27 PDT (-0700)
Viewed: 45 times, last viewed: 2017-06-20 07:02:50 PDT (-0700)
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