Observation 87367: Ochrolechia subpallescens Verseghy, Beih.
When: 2012-02-03
Who: Byrain
No herbarium specimen

Notes: Its on the bark of an oak log, I tried some chemistry, I think its K- (Maybe K+ yellow, though I think that might from the algae), C-, and KC+ pink? I also collected a piece to work on later.

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Interesting timing
By: Jason Hollinger (jason)
2012-02-13 13:20:16 PST (-0800)

An expert just mistakenly corrected one of my specimens accidentally because of a bottle of bleach had gone flat. He just bought it from Target, but on closer inspection, it was dated 2002(!) He told me that PPD crystals can go bad after a few decades, too. (Ha! I’m not so old I need to worry about that yet, though. :)

(I was relieved to see his re-correction, though — I was absolutely sure it was C+, I couldn’t imagine what I’d done wrong. :)

false positives for some chemistry
By: Richard Droker (wanderflechten)
2012-02-13 08:26:18 PST (-0800)

My recollection is that some bleach contains more than sodium hypochlorite, but I don’t know what lichen chemicals are affected.

By the way, I just wanted to use C (on some Melanelixia) and found my reagent had lost its potency. A newly opened bottle (and the bottles are quite large) of bleach always seems to go bad on me fairly quickly, despite efforts to keep it sealed well. Wonder if C solution can be made when needed, or if more concentrated reagent is available in reasonably small containers.

Thanks, Richard
By: Jason Hollinger (jason)
2012-02-05 11:06:00 PST (-0800)

Good to know what’s “really” important. Not knowing enough species in the genus, I still rely on the keys which all emphasize hidden characters like the algal layer and chemistry. But you’re right, most things occasionally have specimens lacking whatever chemistry they’re supposed to have. So relying on chemistry alone is guaranteed to send us astray from time to time. I’d never heard of supermarket bleach sometimes giving false positives for salazinic acid(!) Thanks for the warning. I should grab a wad of those two species to keep on hand for testing reagents. Good idea.

my thinking on why subpallescens
By: Richard Droker (wanderflechten)
2012-02-05 08:54:11 PST (-0800)

My opinion is that for Byrain’s lichen the combination of location, substrate and morphology (compare with http://www.sharnoffphotos.com/... 3rd photo, also on oak) strongly favor O. subpallescens, and that chemistry should not necessarily take precedence. According to McCune O. subpallescens is “ALMOST always containing olivetoric and 4-O-demethylmicrophyllinic acids” (My caps; guessing his information is from Brodo’s Canadian Journal of Botany Ochrolechia papers.) A cautionary note (as I don’t know Byrain) is that the C I purchase at the supermarket should not be trusted, particularly after it has been opened, without testing for a strong reaction on something like Parmotrema tinctorum, and also for false positives on something like Parmelia sulcata.

In the Brodo et al. 2001 key O. subpallescens may be distinguished (from O. laevigata and O. oregonensis) by the continuous layer of algae beneath the hypothecium, which may be seen with a dissecting scope by cutting an apothecium in half.

Ochrolechia spot tests
By: Jason Hollinger (jason)
2012-02-04 10:58:27 PST (-0800)

Come to think of it, sometimes I don’t get much C reaction when applying it on top of the thallus. Like it will show up C+ pinkish slowly or C+ red only in cracks. Maybe there’s some necrotic layer protecting the cortex? But it should be very strong in cross-section. We’re talking about olivetoric acid in this case: very strong C+ red. Some other species, e.g. O. oregonensis, have gyrophoric instead which is admittedly a less decisive fleeting C+ pinkish (although KC should be stronger red/rose). Maybe the thing to do is scratch the surface a bit first with Ochrolechia. For whatever it’s worth I had problems with this genus for a long time before I discovered how much more reliable the spot tests were if applied carefully under a dissecting scope.

subpallescens
By: Byrain
2012-02-04 10:46:06 PST (-0800)

Looks close macroscopically to me, but I was not expecting to even get that far without microscopy. Thanks for the suggestions. :)

Concerning the spot tests, I found that the q-tip created an reaction on the thallus of some other lichens from that day that I have yet to upload rather then on the q-tip as shown here. Though this lichen did not appear to react strongly to C alone at all, maybe it discolored the lichen slightly pinkish. I will test this again under a dissecting scope in the future.

Why subpallescens?
By: Jason Hollinger (jason)
2012-02-04 00:03:41 PST (-0800)

Verrucose thallus and lack of double-margin in apothecia? I’m trying to decide what the alternatives might be with C+ pink cortex. Best I can figure it’s O. subpallescens, O. oregonensis (double-rim), O. montana (?), O. laevigata (?)

Regarding the Q-tip spot test technique, I think we might finally be getting a good triangulation on its limits. Most C+ Ochrolechia are pretty strongly C+. It did show up, though, gotta give it that!

looks like Ochrolechia subpallescens
By: Richard Droker (wanderflechten)
2012-02-03 21:08:36 PST (-0800)

My guess would be Ochrolechia subpallescens. Spores would be larger than those of Lecanora.

Created: 2012-02-03 20:08:19 PST (-0800)
Last modified: 2012-02-03 21:09:43 PST (-0800)
Viewed: 105 times, last viewed: 2016-05-01 19:43:59 PDT (-0700)
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