Rhizocarpon geographicum - Map Lichen

My annual Scottish winter trip was based in Tongue, Sutherland, at the end of January. Our time was bookended by two storms: Gertrude and Henry. Consequently we enjoyed spectacular weather: howling winds whipping the skin off the sea on Loch Eriboll; stinging rain on our coastal walk; spindrift off the mountainsides; snow; hail; sudden shafts of sunlight and cloudscapes to rival the dramatic scenery below. 

In the middle was a day of peace and an opportunity to walk upwards. We set our eyes on Ben Hope, the northernmost Munro and an easier walk than the lower, but more imposing, Ben Loyal. We returned to Tongue via Altnaharra on the longest single-track road segments devoid of passing places that I've ever been on. Quite what we'd have done had we encountered on-coming traffic I don't know. 

Just south of the starting place for the Ben Hope walk is a ruined broch: Broch Dun Dornaigil. Brochs are unique to the north of Scotland, the Hebrides, Orkney and Shetland. Most were built around 2000 years ago in the late Iron Age. Archaeologists still don't agree on their nature, although it is generally agreed that they are not militaristic. 

This one had an impressive array of lichens on one of the large stones on the southern side. There are a number of species but the obvious one is Rhizocarpon geographicum forming the appearance of a map of English counties. 

Xanthoria polycarpa

x20 Xanthoria parietina

Here's a picture taken with my phone through one of the eyepieces of my 'new' secondhand Seben stereomicroscope (an absolute bargain at £64). I think this is going to increase my enjoyment of natural history by a considerable margin. Looking through both eyepieces gives an almost hyper-real image of what you're looking at. Even the kids ("God Dad, you're such a nerdy loser!") have been "wow"ing and "ooo"ing. 
The first thing I looked at was a hawthorn twig (like this one) with Xanthoria polycarpa on it. I'd picked it up on a walk several weeks earlier. Imagine, therefore, my surprise when a tiny insect appeared from beneath the foliose 'leaves' of the lichen and scurried off-field! I have no idea what it was, but when I later viewed an even older specimen of 'King Alfred's cake' fungus there were loads of them (I'm pretty sure they're the same species) crawling all over it. It came with x10 and x20 eyepieces and the object lenses are in a turret which can be rotated from x2 to x4. To be honest, x20 is all I've really bothered with so far.
It's widely found on twigs, especially elder (Sambucus nigra). In full sun it is incredibly bright yellow. In shadier areas it's more greeny-yellow. In the photo you can see the fruiting bodies (the cup-shaped things with darker yellow centres) which contain the spores.

Lungwort

This is a famous lichen: Lobaria pulmonaria. It's famous because it used to be widespread but was wiped out by air polution, to which it is very sensitive. Once gone it takes a long time to recolonise so it remains confined to areas which have always had good air quality. It is usually found on deciduous trees such as (in this case) oak and when found is considered an ancient woodland indicator. 
It used to be collected in huge quantities and used to treat diseases of the lungs (the old Doctrine of Signatures). However it was also used for tanning and even as an alternative to hops for brewing beer!

Cladonia humilis

I had to add this lichen as it is very pretty. It's definitely a Cladonia genus member and I'm pretty sure it's Cladonia humilis. I'll see if I can get that confirmed by a grown-up.

Lecanora campestris

This is a common lichen on brick walls. Again, you have to zoom in to appreciate the tiny apothecia.
This is Leconora campestris. I found it round the corner where it was thriving, with lots of individuals.

Cladonia ciliata var. tenuis

Cladonia ciliata var. tenuis as I'm sure you are all already well aware. This beautiful lichen was noticed on a walk over Christmas on the dunes behind Oxwich bay on Gower in south Wales. I was born on Gower and grew up in Swansea where my parents still reside. It was where the tiny spores of natural history interest first settled, shed by people like Dr Michael Isaac, a Scout leader who happened to be an academic marine biologist. I well recall a 'night hike' under a full moon along the south coast of Gower peninsular 

(incidentally, Gower was the first Area of Outstanding Natural Beauty to be so designated) and seeing Noctiluca scintillans for the first time (also at Oxwich). It was astonishing. I have only seen it once since then, but never as florid. Michael knew immediately all about it and I've remembered the name of this funny little marine organism ever since.

I've made the photo large so you can appreciate better its amazing appearance. How many lichens can you name? Funny really as they're much more visible than even blue tits. The problem is that to appreciate many of them you really need to get up close and personal, preferably with a x10 optical device such as a hand lens. 

Lichens are on my 'to do' list. I have started by borrowing a book by William Purvis called, simply enough, 'Lichens'. (It's published by the Natural History Museum.) Mr Purvis is not to be trifled with when it comes to matters lichenous and this book is a nicely pitched distillation of a lifetime of accrued expertise, pitched at a level commensurate with O-level biology. 

They are a fascinating group because they are made up to more than one organism: usually a fungus, or mycobiont, and an algae, or photobiont. The latter can be green algae, yellow-green algae or cyanobacteria which are invariably 'trapped' by the fungal partner. The lichen is known by the name of the fungal partner. 

The exact nature of the relationship between the fungus and the other partner is still discussed. Mostly the fungus is only found existing as a lichen, although some have been grown in laboratories without their photobiont partners. When this is achieved it bears no resemblance to the lichen, commonly appearing as a mouldy amorphous mass.

I have Simon Davey to thank for the identification (see his blog - Inspired by Ecology). The Cladonia genus is sometimes referred to as the reindeer lichens as they are widespread in the arctic tundra where they form a significant percentage of the diet of reindeer.