Observation 165867: Dimelaena oreina (Ach.) Norman
When: 2014-05-16
No herbarium specimen

Notes: from Diablo burn zone, the following spring after the summer 2013 fire.


teeny tiny apothecia cut in half horizontally, showing white context. razor for size comparison!
teeny tiny apothecia cut in half horizontally, showing white context. razor for size comparison!

Proposed Names

1% (2)
Recognized by sight: some sort of “tile” lichen that survived the fire that swept over the Diablo Summit.
74% (3)
Eye3 Eyes3
Recognized by sight

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Debbie Lichenologist!
By: zaca
2014-05-29 11:04:33 MST (-0700)

Considering your description, there are “funny” lichen observations. Congratulations for your success with lichens, along with the same with mushrooms.
You were a lot fast than me, that continue to look without success for the paper mentioned in my comment.

Congratulations on persistence!
By: Jason Hollinger (jason)
2014-05-29 10:43:38 MST (-0700)

They’re way smaller than they look on photo. Definitely easier with a nice handy chunk in hand under a dissecting scope with both hands free and a nice solid chair under the tush. :) (But still not easy, haha!)

“not easy” was an understatement!
By: Debbie Viess (amanitarita)
2014-05-29 10:30:20 MST (-0700)

first, the damned lichen was awkwardly way up on a rock face, so I had to do this on tiptoe on crumbly rock!

second, I couldn’t even see any apothecia with the naked eye, I had to first use a magnifier (on tiptoe) then attempt to pop off a bit of material; of course the lichen was also growing on a vertical rock face!

as a beautiful survivor, I didn’t want to trash the fb either, so I very very carefully popped off some material with the edge of my razor; a few specks landed in my hand. But there was NO WAY that I would’ve been able to slice them again!

Luckily my original swipe showed the white context clearly, and no lichens were seriously harmed in the gathering of ID data!

Great excuse to go back into the burn, though. Even more fire-stimulated flowers were blooming and the birds were great, too, all for the sake of a lichen ID.

win/win. ;)

Found one example photo
By: Jason Hollinger (jason)
2014-05-27 12:25:37 MST (-0700)

Admittedly this is a Sarcogyne, not a Dimelaena, but this demonstrates a white hypothecium nicely:

If I run across a Dimelaena today I’ll post a photo of it, too.

dang …
By: Debbie Viess (amanitarita)
2014-05-27 12:10:48 MST (-0700)

my razor/boxer cutter got confiscated the last time I flew! ;)

Guess that I’ll just have to sharpen up my pocket knife … using it as a trowel seems to dull that blade, for some reason. but darn it, we WILL have an answer to this (ahem) burning question!

I do have a magnifier for the field, but alas no dissecting scope at home (yet). Yet another reason to put one on the top of my wish list.

gotta keep going deeper … if you want good answers.

So, when I manage to slice that tiny bit of lichen (and hopefully not myself, too) the basal colors will be white for oreina or brown for radiata. SEEMS simple enough …

We’ll see how it works out in practice.

Okay, I see what you mean now
By: Jason Hollinger (jason)
2014-05-27 11:50:21 MST (-0700)

Yes, I’m seeing the greenish tint now. But, yes, let’s not trust those pesky colors and put it beyond doubt. You can do it in the field with a hand lens and razor blade. Just slice one of the apothecia (see photo below, they can be hard to locate in some specimens of Dimelaena) vertically in half and see if it’s brown or white below the gelatinous hymenium. If you’re right, it should be conspicuously white everywhere inside, and just dark at the very top. Wish I had photos to demonstrate both states, but alas, I don’t. And I’m not saying this is going to be easy! I can reliably do this under a dissecting scope, but doing it in the field with a hand lens is another matter. :)

my photo reminds me strongly of yours, Jason, here …
By: Debbie Viess (amanitarita)
2014-05-27 11:38:50 MST (-0700)

of D. oreina: http://mushroomobserver.org/image/show_image/289554?obs=118888&q=1zI4e

I don’t see any brown in my photo. Dark coloration in center is also similar to your photo, just more extensive.

Can one see the hypothecium w/out first scraping off the hymenium? I am fairly ignorant around lichen morphology.

If a green/yellow color in lichens is a function of usnic acid, then this lichen has usnic acid. If the presence of usnic acid makes this oreina, then I would still say that it is oreina over the usnic acid-free radiata.

I added a second photo of the same lichen. I have more photos of other fbs on that rock as well, that show a more yellow leading edge. I’ll add those, too.

I will be returning to the burn this week, and I know exactly where this lichen lives. How can we nail this ID, assuming that I perhaps don’t have the right chemicals at hand?

Just curious, plus, truth be told, I enjoy a spirited taxo-debate amongst esteemed colleagues. ;)

Maybe the yellow …
By: zaca
2014-05-27 10:48:48 MST (-0700)

that we see in the photo corresponds to the part that grew after the fire, while the brownish could be a result of it.

to zaca
By: Jason Hollinger (jason)
2014-05-27 10:48:16 MST (-0700)

I would greatly appreciate it if you could locate that paper! Thanks so much!

Color and chemistry
By: Jason Hollinger (jason)
2014-05-27 10:43:49 MST (-0700)

(Which, of course, are really the same thing!)

D. oreina has usnic acid, giving it a more yellowish and/or greenish hue. It is extremely widespread throughout N. Amer. Also, as it turns out, it has a white or hyaline hypothecium.

D. radiata has no usnic acid, leaving it a more nondescript grayish-brownish (just like this photo). It is more restricted to the coast, being known almost exclusively from California in America. And it has a dark brown hypothecium. (And who isn’t excited by that??) Ooh! And it is usually UV+ bright white (divaricatic acid in the medulla, be sure to scratch the cortex off first).

Lichen resistent to fire:
By: zaca
2014-05-27 10:43:18 MST (-0700)

I remember to see once a paper with a study of resistence of lichens to fire, but I cannot finf it now, though I recall the numbers stated there: of the total amount of lichens resisting to fire, 58% are crustose and about 20% are foliose and also apprx. 20% are fruticose. If I will find that paper, I´ll put a reference here.

these lichens were greenish/yellow …
By: Debbie Viess (amanitarita)
2014-05-27 10:37:02 MST (-0700)

so if that indicates D. oreina over radiata, oreina would get my vote. plus, Diablo is more of an interior rather than coastal location. pretty xeric up there!

Hi Jason!
By: Debbie Viess (amanitarita)
2014-05-27 10:20:27 MST (-0700)

thanks for weighing in. what’s the diff between those two Dimelaena sp.?

Dimelaena for sure
By: Jason Hollinger (jason)
2014-05-27 10:20:17 MST (-0700)

D. radiata may be more likely on the coast, especially given how brownish it is instead of greenish / yellowish. (But that’s a very subtle thing, and the fire could well have changed its colors a bit.)

That’s interesting to me, Zaca, that you say crustose lichens are known to resist/regenerate with fire. I’ve observed a number of remarkable examples of this: crusts which survived in tiny cracks in the middle of huge fires (like the record-breaking Station Fire in southern California), or others (Dimelaena, in fact) which were turned white from a fire which burned every plant and moss off of an outcrop, but the lichen, despite having a thick necrotic (white) layer on top, still had a thriving algal layer underneath throughout, and it was continuing to grow out from the margins and produce spores just as if nothing had happened.

I was wondering if anyone had done any research or published anything about this remarkable ability. Do you know of work from Portugal? or elsewhere?

Yeah, I never saw …
By: zaca
2014-05-25 12:45:42 MST (-0700)

this species, though it may exist here. Crustose lichens, in particular, are known to resist/regenerate with fire. I don´t known if this species is particularly resistent to fire, but it seems it is.

By: Debbie Viess (amanitarita)
2014-05-25 09:04:27 MST (-0700)

that’s a fast ID!

So, are these sorts of lichens known to survive/resist fire? Most of the rest of that rock was burned down to the minerals. neat adaptation.

Created: 2014-05-25 08:39:22 MST (-0700)
Last modified: 2014-05-29 10:20:30 MST (-0700)
Viewed: 80 times, last viewed: 2016-10-22 02:57:20 MST (-0700)
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