Resources to identify lichen


I’d like to learn more about lichen.
Can anyone recommend resources?
I’m especially interested in anything that could help me ID lichen in the south of Spain.

I’ve looked around for websites and books but most resources seem very location specific.



For many organisms that do not have good field guides for identification, especially for a particular region, I would suggest iNaturalist might be the best resource for identifying local taxa.



Not Spain, but I’ve found these helpful starting points in Iceland and UK :


Those links look promising to get started and then iNat will hopefully help me get acquainted with the local species.


I also like using an app called Picture Mushroom for identification. It functions very much like the CV on iNat but takes into account things like the side profile and bottom gills when you’re taking your picture, which I find really helpful. An added bonus is that it contains descriptions that tell you about the toxicity and habitats of the suggested mushrooms.


I’ve gotten the most feed back from my lichen ID’s from posting my observations on Mushroom Observer…primarily from Jason Hollinger. He’s very active on the forum at least for North America but I recall there is someone else near your region too and maybe others. Submit as clear photos as you can (sometimes underside too), substrate, etc.

@jurga_li picks up most of the Unknowns I push to Lecanoromycetes.

Lichens are difficult, especially because many types can’t be identified to species level via photo. I’ve found the best resources to be university or botanical garden publishing presses.

llimona, et al 2001 Checklist of the Lichens and lichenicolous Fungi of the Iberian Peninsula and Balearic Islands is out of print, but you can download it from the ResearchGate link provided.

It’s a checklist, not a key or ID guide though, so it’s not a great help in identifying the species. It’s also well over 500 pages (there are a lot of lichen species in any given area), so even using it as a reference takes a bit of effort.

It’s worth browsing through the NHBS lichen book selection as well. Their titles cover a wide range of areas, but there may be some that are of use.

The van den Boom 2020 Foliicolous Lichens and Their Lichenicolous Fungi in Macaronesia and Atlantic Europe looks to be particularly relevant, although it’s only looking at foliicolous lichens, not crustose or other types.

This volume of Bibliotheca Lichenologica presents a study of the diversity of lichens and lichenicolous fungi on leaves and conifer needles in Macaronesia and Atlantic Europe. Additional information on foliicolous lichens and lichenicolous fungi for many more neighbouring countries (Norway, Denmark, the British Isles, the Netherlands, Belgium, France, mainland Spain, mainland Portugal, the Canary Islands, Madeira, and Azores) is included. A total of 150 taxa are treated, 109 are crustose lichens, 29 are macro lichens and 12 are lichenicolous fungi, 10 species are described as new (8 lichens and 2 lichenicolous fungi). Keys, descriptions, distribution and taxonomic discussions for all species and illustrations for 95 species are presented.

Lichens are often very widespread, so even guides for distant areas may be of assistance at times. In North America there is pretty much no better lichen reference and ID guide than the 2001 Brodo, et al Lichens of North America with an addition in 2016 titled Lichens of North America: Updated and Expanded Keys.

The Nimis 2016 The Lichens of Italy: A Second Annotated Catalogue may be useful as southern Spain and Italy have similar climates and likely share a number of species.


If it’s at all a possibility I would recommend seeking out whether there are any local people interested in lichenology and seeing if you can join them on a field trip or similar.

IDing lichens from first principles is tough; most of the serious books are written for people who already know to filter out the common species and who need to cover everything, and so especially with crustose species will often require microscopy and chemical tests very early on. These are invaluable for the experienced but for a beginner trying to learn the most common species it is like trying to learn to recognise a hazel by counting stamens in the catkins or your friends by measuring the size of their ears.

If finding like-minded people is not possible, iNat might be the next-best thing you have; I learnt a lot as a beginner by simply watching what other people were observing on a national reporting platform here, recognising similar things, and trying to look up descriptions on the internet about whether there were any immediate lookalikes, and then occasionally getting feedback from IDers when I’d messed something up. (Btw, if an IDer makes a disagreeing ID on something of yours and you’re trying to learn, make sure to ask why if you want an explanation. Most people are very willing to explain things if it is obvious that you are seriously interested if a novice rather than simply throwing things at the CV and seeing what sticks, which can otherwise be hard to tell.)

Regarding looking things up on internet sites, it can be very useful, even if they don’t cover your are specifically many species are still shared between e.g. the whole of Western Europe. One site I like that hasn’t been mentioned yet is
Be somewhat careful though, especially if venturing onto less serious sites, I tried searching for things that might be worthwhile to your specific area and as a particularly egregious example I quite quickly found a blog post claiming to show pictures of 30 species lichens of which at least 9 were obvious and frequently severe misidentifications.

As for books and the like that might help specifically in your area the only one I’m aware of is Mediterranean Cladoniaceae which is available as a free pdf:
Cladonia is certainly not the easiest place to start though even though many of the species are large and attractive.

From what I have heard this book is good but it is almost certainly not somewhere you would want to start as a beginner, being an expensive technical detailed monograph of a group of frequently very small and inconspicuous lichens in a very specialised habitat.


If you are a Facebook user, there are a couple groups I highly recommend with many active experts:
Lichens Connecting People:
Lichen Identification:


Lichens are completely new to me. I didn’t know about lichens until recently. I took some pictures of lichens on a recent trip and when I uploaded them to iNat I tagged them as plants. I don’t come from a science background at all, I was humbled to find out lichens are fungi. I thought lichens were similar to algae.

I have some lichens in my observations. They are certainly interesting. When I went hiking in the past I used to wonder to myself “why are people spray-painting all of these rocks yellow everywhere?”

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Lichens are a complex life form that is a symbiotic partnership of two separate organisms, a fungus and an alga.

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Unfortunately, that is, at least in my experience, relatively common when it comes to accurate lichen ID sources.

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For Spain, regretfully there are no good resources. For Europe in general, there are following resources: (archived) (more for professionals)
There are various books for various levels of lichenological knowledge.
But in all cases, all resources have to be used with greatest care: even same species may behave differently in different parts of Europe: their ecology and frequency of occurrence may differ in the areas that are distanced only about 300 km.


Not specific to south Spain, but here you are some resources:

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My experience is different. Especially when it comes to lichens, very few iNat users know them at all.

At my level, I’d be happy just to know whether to ID it as “Common Lichens” or not. It looks like a lot of people automatically put that for any lichen, just so that it will be finer than “Fungi including Lichens”; but then, maybe they really do know how to tell.

IDing all lichens as Lecanoromycetes is technically wrong, but it is wrong rarely enough to be useful, especially with the species most commonly observed, at least here in Europe (mileage might vary elsewhere particularly in the tropics but I don’t know). Otherwise the general choices are Fungi or Pezizomycotina (if you can rule out the rare basidiolichen), and lichenologists are a sufficiently separate bunch from mycologists that it’s much less likely that they will be seen there. As someone who IDs a lot of lichens I would much rather have a few wrong Lecanoromycetes-IDs on lichens I then do see than a lot of Fungi-IDed ones I don’t.

Sadly there is no way to easily tell the difference consistently from macroscopic details, and knowing when to put e.g. Pyrenulales or Arthoniales instead often requires knowing enough that you could get much closer to species as well.

If your lichen has dark perithecioid (opening by a narrow pore), lirellate (long and narrow, often star-like branched) or arthonioid (irregular, without any well-defined margin) fruiting bodies there is often reason to be wary of Lecanoromycetes, but there are exceptions (Pseudosaginea and Graphis are in Lecanoromycetes, Pyrenula and Opegrapha are not).

Even that doesn’t always help any because sterile species or material is not uncommon, and even professionals have been confused at times. For example Normandina pulchella was first thought to be a usually sterile species sometimes forming perithecia, then a sterile basidiolichen with the perithecia belonging to a parasitic ascomycete, and is now once again considered pericarp (and placed in Verrucariales).

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