Observation 109636: Dermatocarpon Eschw.
When: 2012-06-13
(47.4125° -116.591° 706m)
Herbarium specimen reported

Notes: Upper surface smooth, lower surface black papilose, no apothecia, but seems to be abundant perithecia , spores difficult to see, seem to be small and hyaline. These could be pycnidia, but according to keys not as likely as perithecia.

Substrate: Basalt

Proposed Names

-28% (1)
Based on chemical features: C-
83% (1)
Eye3 Eyes3
Based on chemical features: C-

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
I’m afraid it’s not so simple
By: Jason Hollinger (jason)
2012-09-14 12:37:12 CDT (-0500)

The original description, especially of old names, is often completely useless, apparently. And all the type specimens are in Europe. Honestly? There might not be any good reference for Dermatocarpon in the northwest, for example. I’ve tried to get help from Trevor on them before and he just throws up his hands, essentially, mumbling something like “I need more time to work on that group”. Some groups like this, you may have no recourse but to send the specimens to an expert (maybe Heiđmarsson or Breuss in this case?) Frustrating, I know. Or you can just stick with something conservative like reticulatum despite reservations, and wait for taxonomists to catch up.

The last photo
By: nastassja (Nastassja Noell)
2012-09-14 10:59:24 CDT (-0500)

Showing the difference between these 4 is incredibly helpful! Wow.

So what I’m seeing is that there is no farinose dust. So this is not Dermatocarpon reticulatum as McCune’s key indicates.

You know what I wish? I wish Esslinger’s checklist for lichens of NA had the sources for the original description. Sometimes I spend so much time trying to track those down. I’d love to have a library of all of them!!!

Oh, right, forgot to mention…
By: Jason Hollinger (jason)
2012-09-14 03:01:02 CDT (-0500)

I have a picture of this “farinose” thing on ways, I think… Oh yeah, totally, especially look at the very last photo in this series:


Also note that Curtis has a photo from Turnbull up there. :)

Yeah I don’t know what the deal is
By: Jason Hollinger (jason)
2012-09-14 02:57:40 CDT (-0500)

These are old names, D. taminium and D. bachmanianum, but they only started showing up in North American floras in the last ~10 years. But don’t blame Nash, give curses where curses are due – Heiđmarsson and Breuss are the culprits in this case. :)

Supposedly, you can get by with Lugols and C. From Sonoran Flora again: “Lugol’s iodine with chlorine added afterwards gas the same effect as Melzer’s.” But take this with a grain of salt. It’s much easier to read the reaction with Melzer’s in my opinion. The reaction is quick after you add C, then bleaches out immediately regardless of the result. I’m still trying to “calibrate”.

And the whole thing is suspicious, apparently, as the test is just revealing presence of starches or something, which Trevor suspects is an environmental response. My jury is still out (to lunch)…

Erg. Grumble.
By: nastassja (Nastassja Noell)
2012-09-14 02:24:33 CDT (-0500)

D. bachmannii vs D. reticulatum – the distinguishing feature is the “faintly white dust” ?! Nash!

But thank you for all the spore sizes :) and all the goings a through the possibilities. You’re awesome Jason :)

Melzers has got to be around here somewhere… I must say that I did a double take on the D. americanum, kept thinking I was reading U. americana. McCune’s key’s totally lack all of these lovely Dermatocarpons!

I concur with Dermatocarpon
By: Jason Hollinger (jason)
2012-09-14 01:34:40 CDT (-0500)

Only other thing vaguely like it would be Umbilicaria, e.g., U. americana or U. vellea, but both have obvious copious rhizines. Dermatocarpon can have relatively small spores I guess (americanum 10-14×5-7, reticulatum 12-17×5-9, taminium 14-19, bachmanianum 13-20×5.5-8). Do you have Melzers handy? It’s worth testing the medulla (americana Melzers+ red, reticulatum and the rest are Melzers-) Problem is the texture of the lower surface is too variable to be a reliable character, especially with these “new” species. From Sonoran Flora:

1a. Melzers+ red . . . D. americanum
1b. Melzers- . . . 2

2a. lower surface faintly white dusty (farinose), often reticulate . . . D. reticulatum
2b. lower surface smooth, rugose, verrucose or reticulate, never “farinose” . . . 3

3a. lower surface brown to dark brown, often with reddish tinge, sometimes moderately reticulate . . . D. taminium
3b. lower surface dark brown to almost black, usually reticulate . . . D. bachmannii

Good luck! :)

Created: 2012-09-14 00:42:15 CDT (-0500)
Last modified: 2012-09-14 11:02:46 CDT (-0500)
Viewed: 56 times, last viewed: 2016-10-22 11:55:59 CDT (-0500)
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