I never thought I would become interested in lichens but, after photographing a few species during a trip to the Austrian Alps in June 2023, I decided to give them a bit of attention as they are definitely another 'small world' nature subject that

I should be discovering.

   

Unfortunately, we don't have comparable locations in Dorset, nor indeed any upland areas, but lichens grow everywhere, and with some good woodland and heathland sites nearby, and the coast not that far away, I have plenty of habitat options. I regularly visit most of these places, so why not take a break now and again from photographing insects. And, why not have a section of the website for species seen further afield, such as the lichens I photographed in Austria, especially as most of those species also occur in Britain, albeit mainly in Scotland. Although I want this site to continue to focus on species found locally in and around Dorset and the New Forest I think, that in situations like this, it would be rather daft not to include them.

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I wasn't sure whether to catalogue the lichens I've photographed by their growth form as described below, or by habitat, but decided on the latter as it made more sense, and it was a convenient way to separate the alpine species; there are

four main categories; Montane, Woodland, Heathland and Coastal, plus a small Urban section at the end.

 

Although each section includes a brief preamble, it's important to have some understanding before looking more closely at the individual species so, with the small amount of knowledge that I've gained, here's a very basic introduction to lichens.

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Pick up a field guide, and one of the very first questions, is "what is a lichen?" The simple answer, is that they are a combination of two different organisms, fungus and algae, which grow together as a mutually benefitting partnership. The fungal element typically makes up the bulk of the body of the lichen, known as the thallus, and the algal cells are buried within it.

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The next question is usually associated with the way they grow, where they grow and the substratum on which they grow? The habitat preferences are confirmed on the individual species accounts, but the growth form which, in this context, is best referred to as the thallus type, needs explanation. The main forms are; Crustose, where the thallus is closely appressed to the substratum and cannot be easily removed without some damage to the substratum (there's a variant of this form known as Crustose-Placodioid, which has lobed margins, but that can be discussed later); the second is Foliose, where the thallus is made up of leaf-like lobes; and the third is Fruiticose, which has a shrubby or bushy thallus attached at a single point, known as the holdfast. There are other types, including Leprose (a crustose lichen with a powdery or dust-like appearance); Squamulose (with a thallus consisting of small, scale-like plates, called squamules), and another known as a Cladoniform lichen (which encompasses two growth types, squamulose and fruticose, the latter, which in this context is called the podetia, being the structure that supports the lichen's fruiting body), but Crustose, Foliose and Fruiticose are the three primary forms.

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Another thing to know, or at least have a basic understanding of, is to do with the way lichens reproduce. This is important as the different forms play a major role when you start trying to distinguish individual species. Again, keeping this as simple as possible, there are two main methods. The first being sexual with fruiting bodies, and the other being asexual reproduction where finger-like outgrowths (isidia) or sugar-like granules (soredia) break off to start new lichens. With the sexual method, the lichen ascocarps are either cup-shaped apothecia with the hymenium exposed and lining the cup, or perithecia, which are flask-shaped fruiting structure that are typically imbedded within the thallus. Apothecia are further defined as being either lecanorine (where the cup has a thalline margin containing algal cells) or lecideine (with a proper margin where the rim is often the same colour of the disc). A further form is lirellate where the fruiting body is usually at least twice as long as wide, often slit-shaped with black carbonous margins. Once again though, I have to note that this is a rather basic explanation as there are other features and additional information that would be useful to know.

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As can be seen, there are many specialist terms that apply to lichens that need to be understood without constantly having to look them up. I don't mind admitting that I found that aspect of reading through descriptions very challenging but, over time, I've started to become a bit more familiar with them and now have a better appreciation of why they're needed.

 

Whilst the British Lichen Society (BLS) have a very comprehensive glossary and guidelines for the terms that should be used by authors of published material, I've tried wherever possible to simplify what I've written, but at the same time making sure that my abridged text makes sense.

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Finally, please note that although I've been as careful as I can in cataloguing all of these species, including seeking expert help and making qualification when an identity cannot be reliably confirmed visually from photos alone (as is the case with a number of species), there are bound to be some errors and/or misidentifications. Having started with absolutely zero knowledge, this has been a rather challenging journey of discovery to get this far, but it's an ongoing project that can be corrected and added to over time.