Observation 47168: Sticta Ach.
When: 2010-06-19
Collection location: Sintra, Portugal [Click for map]
Who: zaca
No herbarium specimen

Notes: This is the second observation of this Lichen.The first one is in MO#46871 and, as mentioned there, the lichen covered an entire wall in a pine forest. This time the wall still exists, but the lichen almost desapeared and the remaining part of it is drying (last attached photo), having now a much darker color. According to the comments made by Jason in MO#46871, the lichen must belong to the genus Sticta, since the underside face have some rounded holes. However, the upper side is not easy to describe: I was not able to identify apothecia, some parts seem to have granules, the margins have tiny little lobules and are very irregular.

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Add Comment
Chemical reactions
By: zaca
2010-06-22 17:32:40 CDT (-0400)

I forgot to add in my previous massage the results of the chemical reactions:
K+yellow, KC+gold.
I have used K=KOH (20%) and C=sodium hypochlorite.

By: Jason Hollinger (jason)
2010-06-22 17:11:47 CDT (-0400)

I’m sorry, I was trying to say it was not S. fuliginosa, but that that was the closest species in North America. Yes, I’m not at all surprised you have such a thing as S. dufourei which I’ve never heard of. Looks very promising.

By: zaca
2010-06-22 16:56:49 CDT (-0400)

Let me start saying that I feel happy with the course of this observation and that for me to know the genus for this specimens is already very good. Please understand that I’m just starting with lichens. However, I would like to share the doubts of Jason in classifying this specimen as S. feluginosa. In fact, I was looking again to the piece of specimen that I brought with me. This time I isolate a “leaf” (~2 cm across) and take some pictures of it; I upload two of them. After I search the internet for pictures of that species. in the site
www.sharnoffphotos.com I found 9 pictures of the upper side: there are no possible comparison; my specimen is much more lobulate. I also saw other pictures of this species and the same conclusion can be drawn. At the end of my seach I found another site, www.stridvall.se,
with pictures of this species, but also has pictures of another species, S. dufourei. In some of these pictures the marginal lobules are even more marked that in my specimen. The color also match. Is this species another possibility?

You are very welcome
By: Jason Hollinger (jason)
2010-06-20 18:17:03 CDT (-0400)

Spores are critical for the crustose or so-called “microlichens”, but they are typically useless or at least unnecessary for the “macrolichens” (such as the ones you’ve been posting — the leafy and bushy and stalked lichens). Chemical spot tests are more useful, particularly K = KOH (lye) and C = bleach.

For higher taxonomy, spores are useful but details of ascus and apothecium anatomy are also used. For example, the family Teloschistaceae is separated from all others by the presence of “polarlocular” spores — smooth, colorless, elliptical spores with two compartments separated by a thick septum with a minute canal joining the two. It is a very distinctive spore type, and in this case not shared with any other group of fungi. However, that is an unusual case. Look at the much larger Lecanoraceae, for example, all of which have plain old smooth, colorless, elliptical, single-celled spores. Not much you can do with that. Instead they look at the structure of the apparatus at the tip of the asci that’s used to launch the mature spores up through the epihymenium into the air above the apothecium. This is very difficult to observe without a high-quality microscope (my scope isn’t good enough) and lots and lots of experience.

Lichen species probably have a much larger range of variation than most naturalists coming from other fields are used to. The critical thing is to throw away previous notions of color and form invariance and relearn which characteristics are invariant for this new group of organisms. A professional lichenologist can identify macrolichens (and in exceptional cases even microlichens!) at a glance in the field, no matter how malformed due to variance of habitat or microclimate. It can be done. I’ve seen it. Don’t lose hope!

As an example: your species of Sticta can probably be anything from brownish to pale gray to almost black depending on exposure and moisture content, however it will always have identical gaping holes underneath, and most likely the coverage of tomentum underneath will be fairly reliable. The quantity and extent of the little granules and lobules on the surface and margins is probably also highly variable. But I would expect all specimens of the same species to have at least some of both (you may have to look closely with a hand lens).

This is why I doubt that yours is S. fuliginosa — I’ve never seen the marginal lobules before. The last time I saw something like that it turned out to be a rare species I’d never seen before that my literature didn’t cover. I think in this case it is more likely that you have another species over there that I’ve never heard of, than it is that S. fuliginosa has such a broad range of variation. But that’s just playing the odds.

It is worth noting that you have an unusually healthy population there; I would expect other populations to show less well-developed lobules and isidia.

Thanks, Jason, for all the information.
By: zaca
2010-06-20 17:16:53 CDT (-0400)

I’ll be attentive to the details you mentioned in you comments related with this species.
I do not want to bother you, but I have two simple questions related with Lichen: (a) I seached the internet in order to find information about lichen spores and I found almost nothing: They are not used to classify lichen (as they are used to classify fungi)? (b) is it expectable that, for example, lichen similar to the ones in this observation will appear in the same place in the future?

Sticta for sure
By: Jason Hollinger (jason)
2010-06-20 14:24:20 CDT (-0400)

Good, as you say, this is Sticta for sure. It looks a bit like S. fuliginosa which does reportedly grow throughout coastal Europe. I hesitate only because I’ve never seen the abundant marginal lobules that yours has. But my experience is from the interior mountains, not the coast.

Created: 2010-06-20 09:04:18 CDT (-0400)
Last modified: 2012-03-01 18:44:25 CST (-0500)
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