Separate Lichen and Fungi into two Categories?

Greetings,

I am fairly new here, so if there are genuinely useful reasons for keeping Lichen and Fungi together in the same broad organism category, I would appreciated knowing them. Before posting this I did a search of this forum and this topic/request has apparently not yet been raised.

So far, separating them seems to make a great deal of sense, both taxonomically and for practical reasons.

For example, I would like to subscribe to Lichen without receiving the avalanche of Fungi.
I can narrow my search using Lecanoromycetes, as this includes the bulk of lichens (given that scientific classification currently uses the main fungal partner’s name), but this is not as inclusive an approach for the broad groups of users as being able to use “lichen” to search.

Also, in the interests of keeping up to date with the science, lichen are no longer considered to be a type of fungi. In order to discuss them accurately, we need to be able to speak regarding the multiple partners in this symbiotic relationship.

Thanks for listening and I look forward to responses.
JP

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I can see adding fields/annotations for the other symbiotes, but in practice, I assume lichens will continue to be referred to by the name of the ascomycete mycobiont, because that’s the only part of the symbiont that’s recognizable in the field/from photos. I wouldn’t expect the photobiont or basidiomycete mycobiont to be identifiable without serious microscopy or molecular work. This is consistent with current references like Esslinger’s checklist.

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Surely it’s the other way round: lichen and fungi must be kept in the same category because there is currently no widely accepted scheme for separating them.

While acknowledging the valid points of @choess and @bazwal, I want to agree with the more practical appeal of @lichenthusiast-jp. If we have even one lichen enthusiast on the site who is willing to help reduce the huge lichen ID backlog, what would it hurt to make it easier by giving lichens their own broad category on iNaturalist? As it is, many of the higher taxonomic categories we use are units of convenience more than of strict adherence to taxonomic norms. And maybe additional lichen experts would be more willing to join in as a result?

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I don’t see how you’d be able to do that without wrecking fungi as a whole: lichen-formers are polyphyletic, so this isn’t as simple as, say, recognizing birds as class Aves and leaving a paraphyletic Reptilia. The best solution for a would-be lichen observer would probably be to watch Lecanoromycetes, Verrucariales, Pyrenulales, and perhaps a few others, which should bring in the bulk of lichenized fungi.

Some things that might help are:

  1. a taxonomic cleanup of the higher levels of fungal classification (inaccessible to curators). If the site admins could draw on Index Fungorum to get it arranged and complete to the subordinal level…
  2. a brief guide for generalist identifiers would be useful, to sort fungi or perhaps just macrofungi into common phyla and classes. I think most of us are more familiar with major plant subdivisions than major fungal subdivisions, and better sorting at the beginning would make it easier for specialist mycologists to work on identifying the group of their choice.
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Yeah, as your second suggestion recognizes, it’s getting them into those groups to begin with that is the issue. I wonder if just having an otherwise taxonomically “empty” Lichens category, overlapping with (or within) “Fungi (including Lichens)” would help get Lichens identified more efficiently. We don’t have to assign any species to it, just have it available as a label or “bin” for observers and identifiers to use, to jump-start the sorting and ID process. Many users (including me) know a lichen when they see one, but not much more. And many users (including me) may not have the time to consult a guide to the major subdivisions of fungi.

It’s these practical issues that probably explain why we still call them “Fungi (including Lichens)”. Lichens are highly recognizable, not “just” fungi, and not often thought of as fungi by the untrained observer.

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Thank you all for contributing these interesting points of view and responses!

A couple of things in response to concerns and questions raised above;

  • Separating lichen from fungi seems unlikely to have a significant impact on fungi: Most of the fungal species involved in lichens are not observed living independently in the wild. Those genera that contain both lichen-formers and (as best know so far) non, e.g. Stictis, could appear under their respective Lichen or Fungi category. This could be a useful educational opportunity during identification conversations. Doesn’t seem likely to cause a problem given that I assume that one could select out both Fungi and Lichens in order to produce a list or report for both?

  • I don’t know if this move would attract more identifiers or not, but it would certainly be easier to deal with, and it seems like it would make a more methodical approach possible. I’m trying to stay tentative here in my opinions, because, again I am newish here, and there may be impacts I don’t see. Perhaps one of the lichenologists on this site will chime into this conversation (unless you are here already).

  • I agree that it is likely that lichens will continue for a long time to be identified by the name of the one fungal partner in scientific classification, for various reasons, reasonable and otherwise. As some eminent lichenologists have pointed out, only the common names have any real validity as names for lichens at present.

  • However, this is not due to a fungal partner’s recognizability. An argument could be made that, at least for macrolichens, the fungal partner is the least recognizable in the field: Where these have been grown independently, they do not resemble the lichen. In contrast for example, I regularly run into free-living Trentepohlia alga, which aside from being a bit fluffier in that state, is quite recognizable while in partnership within various lichens. A lichen is the product of the partners involved, not of one of the fungi.

  • @jdmore - I find your suggestion of an additional/empty category interesting! I don’t understand this site well enough to visualize that, but if it added a lichen designation, I expect that would allow a sorting function in the filter menu?

I hope my responses are useful. Thank you all again for weighing in on this!
JP

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Yes, that would be about the only purpose for it, to allow identifications of “Lichen” which could subsequently be searched and filtered by potential identifiers. Any finer identification would be of a taxon already under the Fungi (including Lichens) “taxon”, where it would remain thereafter.

Well, the site is built around a hierarchical Linnaean taxonomy, so I’m pretty sure that re-engineering it to allow “overlapping” is a non-starter. I think the correct approach for this, as the site is set up, would be a fungus-specific annotation field, “Lichenized (y/n)”, which would allow observers and identifiers to indicate that a particular fungus is a lichen.

In practice, @lichenthusiast-jp, I think you might be using the wrong tool for your needs. Except for rather narrow taxa or places, subscribing tends to quickly overwhelm your personal feed in iNaturalist. I think what you may want to be using is the “Identify” tool (in the top toolbar). You can set a particular taxon and place to examine, there, and the “Filters” button allows you to set other criteria as well. When I punch in “Ascomycota” as the taxon in the default view (that is, it is showing me all observations of Ascomycota that have not yet been identified to species level by at least two people agreeing), I get about 80% lichen observations. Looking at observations IDd only as “Kingdom Fungi” (and not more specifically), 95%+ of them seem to be mushrooms and shelf fungi.

So I think lichen observations are getting pushed pretty efficiently down into Ascomycota and lower levels of classification. The AI probably helps with this–in fact, I suspect one of the biggest issues in our lichen observations isn’t that they’re labeled as “Fungi”, but that people are identifying all of Parmeliaceae as common greenshield, say, because that’s the first suggestion the AI spits out.

I suggest plugging “Ascomycota” and a suitable place into the “Identify” tool and clicking away–in practice this is how I identify ferns, and believe me, we never run out!

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You can refine the identify filters to include multiple taxa, as well as to exclude certain ones, by modifying the url.

For instance, I can make a url that only shows observations identified in Ascomycota that have not been identified as non-lichen forming classes, and then add to that observations of each of the basidiolichen genuses. Here is a partial version of that:

https://www.inaturalist.org/observations/identify?place_id=any&taxon_id=48250,118252,175541&without_taxon_id=53539%2C55523%2C152032%2C152029%2C55174%2C372751

See How to use iNaturalist’s Search URLs - Wiki to learn more about how to do this.

I agree that looking through observation identified only as Fungi to find lichens would be too tedious, so this is probably the best approach. But maybe you could experiment with searching for words people might write in the description for lichen observations. When I tried it with “lichen”, it was completely useless since it appears that it searches the common name for Kingdom Fungi as well, which is “Fungi (including lichen)”. Changing locality/language settings might possibly get around this.

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Agreed that we definitely stick to hierarchical taxonomy as a good rule. But no re-engineering would be needed to add a non-conforming taxon (grafted or ungrafted) – any curator can do that right now. It would just need to be blessed by Staff and “locked” to be a persistent category. But that said, if other adequate approaches already exist, those would certainly be preferable to a non-conforming taxon.

Me not being a Lichen person, I think your overestimating the capability of laypeople distinguishing what is “lichen”.

The green and white scale on rock, lichen!
mushroom, Fungus!
orange/yellow scale, Orange Terrestrial? Sunburst Lichen?
Leafy greenish, Liverwort? Peltigerales?
Thread-ish, hanging from branches, Moss :)? Beard Lichen? Airplant?

I think separating them out would result in more things left at “Life”, or put into the wrong category. Much like what happens to Kingdom Chromista, Phylum Rhodophyta, Phylum Chlorophyta, and Phylum Charophyta

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yeah i am an ecologist and if i don’t recognize it i still put it in as ‘lichen’ which goes to fungi. Not that I wouldn’t be willing to learn more high-level lichen ID but i doubt we will get everyone to do it

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Excellent points all! Thank you again for all these ideas and for pointing out the various implications: I will think on, and try out your suggested approaches.

Your comment on the common greenshield @choess answered a question for me: I had initially been excited to see a significant number of locations for this species in an area where they were not known to be … until I went through them one by one to find they were actually all Parmelias or Punctelias. Now I know why that was such a consistent choice.

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Isn’t this also the same situation with Butterflies and Moths (Lepidoptera)? There is one subgrouping of “Butterflies” (Papilionoidea), but no single “Moths” subgroup, but rather hundreds of different moth subgroups (Acanthopteroctetoidea, Adeloidea, etc). There might be a reason that situation is different. I’m not a biologist :)

Would it be possible to set up a Project that includes all observations of all the subgroups of “Lichen and Fungi” except the fungal ones, and then lichen enthusiasts could just follow/join that? I’m not completely sure how things get added to Projects and maybe it only happens if the observer has joined the Project, or if someone adds it manually?

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The current scientific thinking is that Butterflies emerged from within moths around the time of the Geometrids. Essentially, it may help to think of them as moths but more “the popular kids,” glorified diurnal moths usually given a lot of attention what with many showy colors and common daytime association with flowers. I’m very new to studying lepidoptera so perhaps this wasn’t a great explanation but someone else can jump in and start a new Lep thread if more questions arise. In the meantime…From bug guide:

Common practice is to divide the Lepidoptera into two (or three) groups, though this is not, strictly speaking, a taxonomic division. (Butterflies and skippers are a monophyletic group within the Lepidoptera [Papilionoidea], but “moths” are a paraphyletic group.)

As for the Lichen separation question…I can’t speak to the intricacies of taxonomy and best ways to handle the user experience versus the integrity of the language and groupings but I can say that anything that is done to separate such groups for ease of use should be very clearly marked as something outside of prevailing (or iNat accepted) taxonomy authorities and just for practicality.

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No - it’s much more like, say, herbivores amongst animals. Lichenisation is a way of making a living, rather than a taxonomic grouping. It independently evolved multiple times within the kingdom of Fungi. About one fifth of all modern fungi are lichenised, and they form an extremely diverse group of organisms. The only real similarity between them is their adoption of the same ecological strategy. They cannot be grouped together in a coherent way by means of evolutionary relationships (i.e. shared descent).

It would appear that there are already some projects like that: https://www.inaturalist.org/projects/search?q=lichen.

However, the few that I looked at (such as Lichens UK), don’t attempt to include all lichenised fungi - they just focus on a few major groups (like Lecanoromycetes). There are some old-style projects (such as Earth’s Lichens) that might be more inclusive - but they don’t seem to show the exact rules used for including observations, so it’s hard to be sure. Anyway, a very long list of taxa would need to be specified to get all and only the lichenised fungi (about twenty thousand species world-wide).

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I’ve done a similar thing for slugs, and someone else has done something like that for edible plants and fungi, which are also not valid taxonomical terms. I couldn’t find any but a similar thing could be done for trees or any other collection of random organisms if you have a list of taxa to include and/or exclude. You can edit the list any time so I would just start with something and gradually adjust it until it fits the/your definition of “lichen”.

Having them collected in a project is convenient because then you can just click the “Identify” button on the project page and it’s all sorted out for you already, instead of having to bookmark a link with all the filters.

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I learn more with every reply - thank you all.

I am getting a better picture of the issues that challenge iNaturalist in this, and I will continue to look at the excellent suggestions brought forward for addressing the practical efficiencies in search functions.

It is important also to note the fact that while one fungal partner in a lichen carries the name and shares evolutionary relationships with fungi that are not part of a lichen, a lichen results from a partnership of organisms from multiple kingdoms, rather than a method of survival belonging to one partner. The term “lichenized fungi” does not represent this well.

It has been an exciting time in the lichen world lately and I am so grateful to the lichenologists actively engaged in research, reporting their work and findings on this subject.

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It’s not intended to. It represents a characteristic shared by all such fungi, not the composition of an individual organism. (That’s the way I was using it, anyway).