Geoffrey Haigh

@geoffrey311.bsky.social

1091 Followers 249 Following

Lichen dabbler and photographer, Anapana-practitioner, sky watcher. I'm really here for the #lichens, but keep getting distracted by the wonderful #landscapephotography And in an age of war and inhumanity, extremism and violence, I repost other things too

Take the worst thing you can say about Hamas, multiply it by 1,000 times and it still will not meet the Israeli repression and killing and dispossession of Palestinians - Gabor Maté, Holocaust survivor

Sign held up by elderly man at peaceful, silent protest, for which he was arrested by West Yorkshire Police. For those who cannot see the image, the sign, reads "'Palestine Action' explained. [cross] Unacceptable Palestine Action Spraying military planes with paint. [tick] Acceptable Palestine Action Shooting Palestinians queueing for food © Private Eye no 1653" Originally published in the satirical magazine Private Eye.

A foliose lichen growing on a tree trunk. The upper sides of the lobes is a yellowish green, the undersides are very pale with a tinge of brown.

This lichen was growing at a point I could barely see or reach on a mature birch tree, obscured from view by a big branch, and if I moved round the tree the ground fell away. I suspected it was Lobarina scrobiculata but wasn't sure. It was at the highest point I could touch, and pushed my camera up to it. Here's the photo.

This species can be a blue-grey colour when it's hydrated, but in the hot dry weather while I was on Rona it had dried out to this pale green. These lobes are quite young – a good sign because it means it is growing – because there is no soredia on them. It usually produces grey soredia on the margins and the ridges.

The upper surface is described as "scrobiculate" which means it has shallow depression separated by shallow, rounded ridges, and hence the name.

The underside is pale with a pale brown tomentum. This brown tomentum on the lower surface is a key distinguishing feature from other Lobaria species. If you enlarge the upper left corner of the image, you can just see it.

This means I've now found three of the four former Lobaria species that were recorded on Rona in 1990.

A dark brown foliose lichen with white pseudo-cyphellae on the lobes (remember yesterday's cyphellae?), with a number of apothecia down the left edge of the photo.

Apothecia are the structures which produce the fungal spores by which this lichen reproduces. There is one small apothecium, closed up around the disc, and three much older, fully open discs, red-brown in colour.

We saw this on rocks up near the summit of Meall Acairseid. On that occasion I did a K-test to check it was not another species I keep looking for. I did the same here. Having scraped away some of the upper cortex from one of the lobes I put a drop of KOH (potassium hydroxide) onto the white medulla of the lichen. It immediately turned yellow, then after a short time it turned red.

If you're still scratching your head trying to remember this one, here is one clue. Foliose lichens with white pseudocyphellae along the margins and on the upper surface, many of them linear, usually belong to the genus Parmelia.

This glossy dark brown species is Parmelia omphalodes. In NW Scotland it frequently covers the top of large boulders or rock outcrops.

The Sticta genus (or family of lichens) is related to the Peltigera genus. We looked at two Peltigeras over the last two days. I was excited to find several places where Sticta sylvatica was growing quite profusely, on rocks at the top of "Primrose Alley" and on the stones in the walls of the ruined blackhouses in the township.

Sticta lichens are rather special because they are usually associated with old woodlands. They are members of the Lobarion community of lichens, which includes the four former Lobaria species, and other unusual lichens associated with ancient woodland.

Growing on a horizontal branch of a tree was this distinctive lichen. It's quite abundant in some parts of Britain, but is also quite beautiful. This is Parmotrema perlatum.

If you enlarge the image you'll see what's distinctive about it, in case you find it in the woods on a broad-leaved tree.

It's a foliose or leaf-like lichen which may be pale grey to pale green, depending on how hydrated it is. The underside of the lobes is dark, brown near the margins and black in the centre. The lobes are attached to the bark by rhizines in their centres.

See how the margins of some lobes are covered with a thick pale substance. This causes them to fold into short, tight bends. The substance is fine soredia. It's composed of very small clusters of both the fungal cells and the algal cells of the lichen. When they become detached, if any of these clusters ends up in the right sort of place, they can grow into a new lichen.

Isidia on Parmelia saxatilis – small and narrow, pin-like

Here's a large rock lying beside a grassy path and beneath a number of large old birch and willow trees. You can see why I nicknamed the path as "Primrose alley". The rock is a piece of Lewisian gneiss, an ancient metamorphic rock. There are some bare patches on the rock, but much of it is covered with moss and lichens. Look closely and you'll see three different lichens here.

All three often grow on trees, but are sometimes found beneath the trees on rocks in humid environments.

The one to the left is Lobaria pulmonaria, which we've looked at in previous posts.

There are two species of Ramalina that are found on coastal rocks. This one is Ramalina cuspidata. If you enlarge the right-hand branches of the lichen in the foreground you'll see a lot of black dots along the branches, all at the tip of small white swellings. These are pycnidia, one type of spore-producing structure. In the centre of the photo a circular structure is attached to another of the branches. This is an apothecium, a second type of spore-producing structure.

A number of features help to identify Ramalina cuspidata and separate it from Ramalina siliquosa (which will be in the next photo).
1. Its branches are narrow and either flattened or ±rounded in cross-section.
2. The branches are blackened right at the base, as they arise from the holdfast on the rock.
3. The conspicuous black pycnidia we've already seen.

Ramalina cuspidata also tends to occur lower down on the shore than R. siliquosa.

Coastal rock covered by a mixture of lichens. Much of it is black, this is the Hydropunctaria maura we've seen before. On top of the black there are pieces of two bright yellow-orange species, one foliose and one crustose. There are also small pieces of a much more orange species scattered about. Pale grey and white lichens are also represented. This is quite a mixture.

This is the black crustose lichen that is mostly responsible for that prominent black zone around the coast. This is Hydropunctaria maura. In Latin, maura means dark or black.

At the top of the zone there is some overlap with the orange zone, hence the appearance of the yellow lichens here. We'll look at those tomorrow. Can you see a second black lichen here?

The surface of the H. maura is often slightly roughened, or it may be glossy. The crust is usually divided into small, neat areoles by cracks that develop in it.

Blue sea at the bottom, below steep coastal rocks, then a rough grass and heather hillside, with blue sky at the top.

Some of the colours on the rocks are the lichens growing on them. A black zone is usually found on rocky coasts, just above the high water mark. This is not a deposit of spilt oil, but a black lichen growing on the rock.

Above the black is usually an orange zone. A number of orange lichens grow there, able to cope with salt water splashing them, but not as well as the black lichens.

The orange zone grades into a grey zone, of lichens able to cope with sea spray but not direct regular splashing. The grey zone then slowly grades into lichens usually found on inland rocks. The sea may still influence the lichen flora for a mile or more away from the coast.

Below the black zone is the barnacle zone where the rocks are submerged twice a day. Other lichens may sometimes be found between the high water and low water marks. No lichens grow below the low water mark, where rocks are permanently submerged in the sea.

In this post we look at a couple of lichens found in the lowest, the intertidal zone.

A small reddish-brown multilobed thallus just over 2 cm wide (scale in mm). There were many of these small thalli dotted over the rocks at the top of Meall Acairseid ("Anchorage Hill") which at 125 m was the highest hill on Rona, overlooking the main harbour.

This is Umbilicaria polyrhiza. The upper surface is smooth and plain. Black rhizines can be seen poking out around the margins and where there is any damage to the lobes. What are rhizines doing on a lichen which has a central holdfast? Well, they play no part in attaching the lichen to the rock, and so technically they are called "rhizinomorphs", structures in the form of rhizines. What role they may play in the life of this lichen, I have never heard.

Stereocaulon lichens are mostly found in upland areas growing on siliceous rock. The name means a stiff or solid stalk, and it refers to the podetia which grow out from the rock. This lichen is similar to Cladonias in having two thallus forms. First a crustose or squamulose primary thallus develops, but that usually disappears early. Then a fruticose secondary thallus develops, of stalked and richly-branched, usually erect, podetia – or, pseudo-podetia as we ought to call them, for unlike podetia on Cladonia species, which are hollow, these ones are solid.

These pseudo-podetia are a little like the branches of shrubs which are covered in leaves – or in this case, with tiny phyllocladia. To identify the species we need to study these phyllocladia. Use a 10x lens, a microscope, or (in this case) take a high-resolution close-up photo.

This one is Stereocaulon vesuvianum. I've heard two explanations for the name. One, rather fanciful, is that the pseudo-podetia resemble a column of steam or ash rising from Mt. Vesuvius. But I don't think they do. The other, more mundane, is that the species was first found and described on the slopes of Mt. Vesuvius.

Here are two crustose lichen on the big boulder, both fairly nondescript, one off-white and one pale grey. You can waste a lot of time with that sort of lichen. If you can't get anywhere with them, you need to walk away and look for something a bit more distinctive. However, these two are both distinctive in their own way. It's just a matter of knowing what to look for.

But first, that black line down the middle of the photo, between the two lichens. That isn't a prothallus; it's a zone of conflict. Neither lichen wants the other one to encroach on its space, let alone steal its algae. The black zone creates a boundary where they can hold each other at bay.

Let's start with the one on the left. With an unknown lichen, start by describing it as carefully as you can. What exactly do you see? Start with the obvious, and move onto less obvious details.

It's a crustose lichen, it's cracked into small irregular areas (areoles) by cracks which reveal a black hypothallus. The areoles are not smooth. Try enlarging the photo. The closer you look, the more you see. The whole surface is made up of small warts ("like fossilised porridge" as one writer put it!)

There are no isidia or soredia, but there are usually plenty of black apothecia. As they grow older they get bigger, up to 3 mm across, and the more irregular the white margin becomes.

This is Tephromela atra, a common lichen on rock; now you may feel you'd recognise it anywhere. But there's a catch - another lichen called Lecanora gangaleoides looks very similar. And sometimes they grow together. How can we distinguish them?

Chemicals won't help much, both are C– and K+ yellow. The trick here is to cut one of those big black apothecia in half, and look at the cut surface just under the black top. If that is dark (maybe with a purple sheen) it's this lichen. If it's pale or greenish, it's the other one.

Another job for a small knife or a razor blade.

Here are three lichens jostling for position one one part of the boulder.

At the bottom, perhaps the oldest one, is Rhizocarpon geographicum, the Map lichen. "Geographicum" is formed from two Greek words meaning "to draw" and "the earth", i.e. to draw a map.

Its greenish-yellow (or yellowish-green) colour is familiar to many people in the hills. Looking closer, the crust is broken into small areas called areoles, and the black hypothallus (the very lowest layer, attached to the rock) is visible as black lines between the areoles.

This lichen does not look healthy. Parts of it have turned black where they have died. I've searched the image for its apothecia, but I don't think I can find any. And two other lichens are growing over it - the large pale one at the top, and some pieces of a brown one in places.

The large pale lichen is also divided into small pieces separated by black lines. It's quite a thick crust, and from this angle we can't quite see to the bottom of some of the cracks, but where we can, it also has a black hypothallus. Look also at its apothecia. They are sitting on top of the areoles. See how contorted the margins of some of them have become. This was a very common lichen which I found on nearly every rock on Rona. It's Fuscidea cyathoides, and sometimes it forms large mosaics.

Then there's the brown lichen. It's formed of small separate pieces, like separate plates. These are almost crustose, but not quite. Look at the top right especially, and then back at the other ones. They are not fully attached to the rock but have free edges lifting from it.

These are separate squamules. It's a squamulose lichen. Its apothecia are very small, and they don't stand on top, but are immersed in the squamules. The discs are darker than the squamules, and usually slightly depressed in it. This is Acarospora fuscata.

In some places it looks like it's holding its own against the Fuscidea. In the middle it seems to have grown over the Rhizocarpon.

Here is the boulder, made of Lewisian gneiss. It has sat here ever since the ice deposited it at the end of the Ice Age, and for ten thousand years lichens have been colonising the parts of it each finds most congenial, jostling each other for space, growing over each other, dying off and being replaced by others. Now, every inch is lichen-covered, and I spent a happy hour or two exploring all over and around it.

These pale grey lobes are Nephroma laevigatum. Their colour depends on their state of hydration, pale grey when dry and reddish brown when hydrated.

This is a special lichen because it is associated with old woodlands. It is often associated with Lobarias and other old woodland indicators. Many of the trees on Rona were not of any great age, they were mostly young silver birch trees, but small pockets of older trees could be found here and there. This old aspen tree must have stood beside the cliff for many years and was still hosting the lichens to show it.

People moved onto Rona in the 1840s when they were cleared from Raasay to make room for sheep. The population dwindled in the early 20th century, and many moved back to Raasay when they could. The last inhabitant left in the 1940s. Yet the island manager told me every piece of flat land on Rona had been cultivated at one time or another. Whatever woodland cover the island had had must have been largely cut down, which fits in with the observation that only pockets of older trees can now be found, on more marginal land.

This is Pannaria rubiginosa, growing as a large patch some 8 or 9 inches across on the rough bark of the old aspen tree.

See how it is growing on a thick, black mat, a hypothallus made of fungal hyphae. On that are some narrow, branching and indented squamules a pale grey colour with white margins. This is not a continuous foliose lichen.

It has many apothecia. Their discs are a red-brown colour and their pale margins are not smooth but "crenulate" – like the crenulated walls of a medieval castle.

One trunk of the silver birch tree with moss and lichen growing on it. All the lichens are bush-like, and all are a similar pale green colour. But they are not all the same.

Most of the lichens have flattened lobes or branches while the one at the bottom has rounded lobes/branches. Those higher up in the photo are a species of Ramalina; the lowest one is a species of Usnea.

When recording I always start with a location reference. I'm in the UK, so I use the Ordnance Survey National Grid. I just take a screen-shot of an app which uses my phone's GPS to get the location reference and the elevation.

This is the bark of an old silver birch tree. There is more than one lichen here, but they are all difficult crustose ones in varying shades of grey and brown. But when the UV light from my torch fell on this part of the bark you can see how the soralia on one of the lichens stood out with a bright fluorescence.

Ricasolia virens (formerly known as Lobaria virens) in a semi-dry state on a tree trunk. This was the second of the four former Lobarias I found, and it is commonly found wherever Lobaria pulmonaria is found (the first of my Lobarias, featured yesterday)

Nothing can be seen of the tree trunk itself. It is completely covered with moss and lichens. On the left of the image is a large patch of R. virens in shades of pale green and brown. Its many small lobes are up to 1 cm wide. Some of these are smooth with the edges turned up a little. Older lobes are wrinkled.

Lots of apothecia can be seen. Mature apothecia are up to 3 mm wide with a red-brown disc and a pale margin, and many of these are turned up at the margins. More immature apothecia are seen growing on the surface of the lobes, smaller and with thicker margins.

This lichen appears to be growing over the mosses and other lichens on the tree. A green moss is trying to reassert itself, growing up between lobes of the lichen. Small podetia from a species of Cladonia are also pushing through between some of the lobes.

A luxuriant growth of Lobaria pulmonaria on branches of a willow tree. I found this on my first day on Rona, and it boded well for my visit to the island.

A tangle of brown tree branches, some several inches thick can be seen, but many parts of them are covered with what look like large pale brownish-green leaves. These are the lobes of the lichen. The weather was warm and dry and so the lichen had dried out, turning this pale colour. Below the branches green grass and other ground vegetation fill the image.

Sphaerophorus fragilis – a many-branched pale grey fruticose (or bush-like) lichen, growing in a mound over a nearly-black foliose (leaf-like) lichen.

S. fragilis is very rarely found with apothecia. As it grows and keeps forming new branches, those that don't bare apothecia are all roughly the same diameter. There are no main branches with thinner side branches. This is the main identification feature for this species. It grows on mountain rocks, often at a higher altitude than S. globosus.

This specimen was on the highest hill on Rona at 125m altitude. It is growing over Parmelia omphalodes.

Looking up into a clear blue sky, as a dark brown eagle with white tail and white head soars effortlessly around, its huge wings steady and motionless.

Looking down one side of a fallen log, a number of bract-like fungi are growing out of it. Many are beginning as a small green knob on the wood, then developing concentric bands in shades of brown and grey

A cast concrete lamppost with some small pale circular patches against a darker background. They are about 2 to 3 cm across.

An Orange Tip butterfly sitting on a dark green leaf, against a pale brown background made up of dead plant debris on the ground. The butterfly has a black body and largely white wings which are held open, but the forewings have a large orange patch on the outer third of their length, followed by a brown border on the outer tip. The inner side of the orange patch also has a very small brown marking.

Wild strawberry: sepals mostly hidden behind the petals; and the terminal tooth of the leaflets is longer than its two neighbours.

Bright green leaves of the wild strawberry, each with three leaflets, and three of the small white flowers, each with five white petals and a yellow centre area with the stamens

Another patch of Cladonia diversa, growing among moss on a siliceous boulder in Woundale.

On the left several very young podetia can be seen, each one clearly growing out of the centre of one of the basal squamules.

The scyphi are well-filled with corticate granules, some of which are beginning to enlarge and grow into small squamules. There are far fewer decorticate areas on these podetia, but they are still present between the granules.

The small cup in the centre of the photo is packed full of these granules and squamules.

Notice too how it is ringed with very bright red dots. It looks like the pycnidia are beginning to grow into larger apothecia, which will produce normal fungal sexual spores when they are mature.

A number of small trumpet-like Cladonia podetia growing out of a bed of small grey-green squamules. There are small red and dark brown dots on the rims of the cups. The podetia were up to 1.5 cm tall.

No prominent red apothecia here, as often found on this species, but the occasional small red pycnidia are enough to identify this as a red-fruited type of Cladonia.

A light-coloured crustose lichen on grey rock, with radiating edge lobes, a sprinkling of grey soralia, but with a damaged central area.

If the lichen had ever had a cephalodium, it would have been there, in that damaged area.

An exposed piece of grey bedrock, which was on top of a minor ridge. Growing on the rock are some mosses, mainly in crevices. On the flat surfaces are quite a few lichens, some yellow, some pale grey, and what caught my eye were a number of small cream rosettes with a pale brown tinge.

Green moss-covered bark of an ancient ash tree. Some patches of very pale cracked bark can be seen between some of the moss. On the bark are five small, smooth, very dark brown, and almost ball-shaped fungal bodies, about 2 cm across. I think these are Daldina concentrica [King Arthur's cakes]

Whole thallus, competing with P. saxatilis on a silicious stone wall, just beside a farm gate in Borrowdale, Cumbria

Three special lichens: top left is a green and brown foliose lichen with prominent raised ridges (Lobaria pulmonaria). Middle to lower left is another green folios lichen with smaller and very smooth lobes, dotted with black structures called cephalodia (Ricasolia amplissima). To their right is a brown foliose lichen which almost disappears against the brown bark of the tree. Some of its lobes are showing the underside of their tips, on which are their red-brown apothecia (Nephroma laevigata).

A black-and-white view across Ullswater to hills on the far side, with a shingle beach in the foreground and the black silhouettes of two trees in the water, against the brightness of the sun. The trees are bare, in their winter state. Other bare trees are growing just on the edge of the water.

A large area of white looking as if painted over the bark of an oak tree, and over bryophytes on the bark as well. There are very few features on the white coating, but it is in fact the thallus of the lichen Phlyctis argena. Some areas of it showed a scattering of pale grey-green soredia.

Examining the lower trunk of a tall beech tree growing among conifers. Where it was free of moss, the whole trunk was covered with a thin white veil.

Lower trunk of a tall beech tree, partly covered with moss, with three grey patches of lichen visible. There were other ones higher up as well.

The front cover of "Lichens des arbres", one of the three books in the "Guide des Lichens de France" series

View from above of the brown, foliose lichen attached to the bark of an old ash tree. The lobes are much smaller than a Peltigera (it is a related genus), up to about 1 cm wide.

Drystone wall with a variety of free-growing algae coloured orange on many of the stones, and a variety of lichens and mosses

Pertusaria pertusa, the "pepperpot lichen", so called because the warts contain multiple small apothecia, each with its own hole. See in normal daylight the thallus is a very pale white-green colour.

On a concrete post in the forest, not much of a thallus but lots of round, shiny black apothecia – thanks Chris who collected a few of the apothecia, and was able to determine this as Clauzadea monticola – a widespread lichen on calciferous substrata, but one that needs microscopic examination to identify.

Pertusaria pertusa with apothecia hidden within large warts (about 2 mm wide) and peeping out through small holes – usually several per wart, hence "The pepperpot lichen"

Bright green lobes of Ricasolia virens, in their well-hydrated state – a special lichen of old woodlands, part of the Lobarion community

The Cumbria Lichens and Bryophytes Group meets, just before entering Naddle Forest –
Group of people on edge of narrow road beside footpath sign

The bare top branches of a sycamore tree, with blue sky above, though with thin high milky clouds

Row of small cumulus clouds over the Arabian desert, one of which has grown into a tall tower. Shadows of the clouds can all be seen on the ground.

Christmas tree and presents

High white clouds and blue sky

Physcia - large, pale soralia - laminal?