Nature Notes from Argyll
(and occasionally other places)
This page was originally written for the For Argyll local news website and is included here unchanged.
Tue 23 Feb 2010 Glen Gallain
On Tue 23 Feb the Seil Natural History Group held a recording
field trip in Glen Gallain, between Kilninver and Kilmelford. Despite
the frosty conditions we had a good turnout of 10 people. All are welcome
on these outings which take place once a month and are described
The object of our visit was a mixed wood of hazel and birch with
some ash. Fortunately for us it was on a south-facing slope bathed
in sunshine which had melted most of the snow, while on the opposite bank the
ground was white and conditions a lot more gloomy. The picture shows the
two sides of the valley, with the ice-covered River Gallain in the dip.
The hazel was of particular interest owing to the rich lichen flora that thrives in Scottish west coast hazelwoods. These woods are of international importance and contain many lichens that are rare on a world scale. The lichens, together with abundant mosses and liverworts, are able to flourish in this "Celtic Rainforest" due to the pollution-free air and the humid conditions resulting from a wet climate with mild winters and cool summers. There is a good article about Atlantic hazelwoods here.
The weather had been exceptionally cold and dry for some time and many of the lichens had a paler appearance than normal. They soon recover their colours after a spot of rain.
Hazel continually puts up new shoots from its base, and these
are initially colonised by thin crustose lichens which wrap around the bark and
are hardly noticeable unless you're looking for them. In a good Atlantic
hazelwood, the young stems are completely covered with these crustose lichens, and there is
no bare bark to be seen.
The left-hand picture shows the map effect formed by the various crustose lichens on a young hazel stem, with dark borders where two lichens meet. The one with black bobbles (perithecia) on an orange-brown background is Pyrenula occidentalis. The one above it to the right, with squiggly black lines on a white background, is Graphis scripta, the Script Lichen, so-called because it looks like handwriting. The one with a greenish tinge below the Graphis and to the right of the Pyrenula is probably Pertusaria leioplaca. The lichen community of smooth hazel stems is known as the Graphidion (after Graphis scripta, one of its main components)
In the second picture we see the next stage in the colonisation
of the stem. Small snaky liverworts are able to cling to the smooth
surface, and grow over the crustose lichens. This one is Frullania dilatata. It has made its way across a patch of Thelotrema
petractoides and a probable Arthonia species, and is about to invade a fine
patch of Graphis scripta. When the hazel stem has a good covering of
liverworts like these, it presents a rougher surface on which more robust
get a foothold.
The next stage is often dominated by Mousetail
(Isothecium myosuroides), the green moss at the top of this picture. The red liverwort to its right is Frullania teneriffae, a
specialist of Atlantic woods. These provide the kind of surface on which
foliose (leafy) lichens can begin to grow, as Sticta sylvatica is doing here.
This belongs to a community of leafy lichens known as the Lobarion. Most
species in this community contain a cyanobacterium rather than a green alga like
the majority of other lichens, and this accounts for their grey or brown
appearance in contrast to the pale blue-green colour typical of lichens in most
woods. As well as providing food from photosynthesis, the cyanobacterial
partner enables the lichen to obtain nitrogen from the air.
The Lobarion is the glory of Atlantic woodlands, and is named after the four Lobaria species which occur there. The left-hand picture shows two of these, the bluish-grey Lobaria scrobiculata at the top, and the green Lobaria pulmonaria (Tree Lungwort) below it. L pulmonaria does have a green alga, hence its colour, but it also contains pockets of cyanobacteria. In this picture both lichens have their "wet" colours; it must have been a particularly humid spot.
On the right is a famous Lobarion lichen, Pseudocyphellaria
crocata (Yellow Specklebelly) which is unusual in having the interior
fungal hyphae yellow rather than white. This can be seen in eroded areas
on the surface, from which small fragments of fungus and alga break off to
As the hazel stems mature they can develop a luxurious growth of these leafy lichens, a sight familiar enough to us in Argyll but unknown in many parts of the country. From left to right here we have the grey Degelia atlantica, the brown Peltigera collina, and a very dry-looking Lobaria pulmonaria.
The Graphidion lichens are almost completely obscured by this
stage, but because hazel continuously puts up new stems there is always a supply
of these for them to migrate to. The succession of Lobarion
lichens is equally assured, as by the time the old stems die and fall over, other stems
will have become ready for colonisation. A hazel in a state of nature has
stems of all ages on the go at any one time.
When old hazel stems die they are often host to the fungus Stereum rugosum (Pink Curtain Crust) which looks rather like a lichen but has no algal component.
The right-hand photo above shows how the Common Dog Lichen
(Peltigera membranacea) got its name - the white rhizines on its lower surface
are supposed to resemble dogs' teeth, and for this reason it was once used to
treat rabies. It was on Hazel but is not a member of the Lobarion; it
will grow in any damp shady place and is often found on disturbed ground
such as beside forestry tracks.
Hazel also provides a vital food supply for many birds and animals. Here a wood mouse has been tucking into its hoard of nuts, one of several such feeding-places we found in the wood. You can tell that the holes are the work of wood mice by the tooth marks being on the outer edge only.
There was also a lot of birch in the wood, a tree with a
completely different suite of lichens to hazel. One of the commonest is
Hypotrachyna laevigata, looking rather dry here and bearing fruits (apothecia)
which are not all that common in this species. It too is a specialist of
Atlantic woods but prefers the acid bark of birch to the more alkaline
hazel bark. The broadly rounded sinuses between the lobes are characteristic of
We did find one mature birch with a thick growth of mosses that
had been colonised by several Lobarion species, presumably able to
ignore the acid nature of the bark as they were sufficiently removed from it by
the moss cover. They included this Leptogium burgessii with its red fruits
(apothecia), and the tiny orange lichen Dimerella lutea
(Tinned Apricots) of which the fruits are the only visible part. Must
admit they look more like tinned apricots when they're wet as the pale rim of
the "tin" then shows better.
A glimpse of the woodland floor with Teddy Bear Moss
(Rhytidiadelphus triquetrus) and frosted hazel leaves.
All photos and other content copyright © Carl Farmer