At the end of February I made a return visit to the area in Glen Cannich that I’d visited last December, which I wrote about in a blog back then. Because of the very short hours of daylight at that time of year, I hadn’t had the opportunity to fully explore that section of the Cannich River then. However, I’d seen enough to realise that there was a lot of interest to discover there, hence the reason for making another trip once the days were lengthening again.
Just before leaving for home at the end of that previous visit, I’d photographed what I thought initially might be a slime mould on a piece of dead rowan (Sorbus aucuparia) wood. Subsequently, thanks to a comment from someone who read my blog and confirmation from Liz Holden, a mycologist who helps with me fungal identifications, I discovered that it was in fact the toothed crust fungus (Basidioradulum radula), and not a slime mould at all.
Returning to the site at the end of February, I was surprised and delighted to immediately find some more of this fungus, on a dead birch branch this time, and only about 200 metres from where I’d seen it before.
There were several different patches of the fungus on a couple of broken sections of a birch branch, with some of them appearing quite fresh, while others, that were more orange in colour, were probably older.
Moving on a bit further, I came to the small island in the river that I’d explored during my previous visit. This time, though, I didn’t go on to the island itself, but explored the south bank of the river, opposite the island, where I had seen some interesting lichen formations on the rocks.
After stopping for a few minutes to photograph some cascades on the arm of the river that separates the island from the south bank, I went to have a close look at the lichen-covered bedrock just upstream from there.
Some sections of the bedrock were almost completely covered by round patches of crustose lichens, which contrasted with the colour of the rock itself. The circular shapes of these lichens were echoed by a depression in the bedrock, hollowed out by a stone rolled there by the current.
The bedrock too had been sculpted by the flowing water, and looked almost of organic origin, such was its gently ridged and rounded shape. I was struck by the contrast between the rapid flow of the water and the almost glacial growth of the lichens – 0.1 mm per year for some lichens like these.
Nearby, I found a rock with a prominent band of quartz protruding from it, and partially covered with a common lichen species – crottle or shield lichen (Parmelia saxatilis).
Because of the damp conditions, the lichens were all fully hydrated and many of them were brightly coloured as well. On another rock, a turquoise-coloured crustose lichen drew my attention.
I began to study the rocks beside the river carefully, as there were a lot of different crustose lichens growing on them. Crustose lichens are those which grow flush against their substrate – in this case the rocks. They secrete acids which break down the surface structure of the rock, liberating mineral compounds which are utilised by the lichen for its growth. When the lichen dies, its organic material breaks down and this is the beginning of the process of soil formation, with the minerals from the rocks becoming available for other organisms.
On another rock, where a little soil had accumulated, there were some fruticose lichens (Cladonia coccifera agg.) growing amongst some moss and liverworts. These are distinguished by the cup-shaped podetia, common to many lichens in the genus Cladonia, and the ring of small red discs on the rim of each of them. These are the apothecia – the structures that release the spores of the fungal partner in the symbiotic partnership between fungus and alga that forms each lichen species.
Cladonias are some of my favourite lichens, and although I often photograph them, this was the only example I saw during the entirety of this day in Glen Cannich. Instead, it was the crustose lichens that continued to draw my attention, and one of the rocks right beside the river I saw a white patch of crustose lichen with a smaller orange lichen growing partly within it. This combination gave all the appearance of looking just like a fried egg, spread thinly over the rock surface!
Another rock was almost entirely covered by an interlocking pattern of the turquoise lichen (Porpidia tuberculosa) I’d seen earlier and a brown lichen (Fuscidea cyathoides).
Some of the rocks were very colourful indeed, with bright orange or yellow crustose lichens growing over them. One rock had a patch of the blood spot lichen (Ophioparma ventosa) which is readily distinguished by its blood red apothecia, and I’ve photographed that species previously in Glen Affric and on Dundreggan.
One large rock had a substantial patch of a white crustose lichen on it. This was the white coral-crusted lichen (Pertusaria corallina), and according to John Douglass, the lichenologist who helps me with lichen identifications, the clusters of white bumps on the lichen are galls.
It was nearing the end of the daylight hours, so I spent the last few minutes before I had to leave in an area where there were a lot of small boulders jumbled together, and all covered in bright orange and white crustose lichens.
Slightly reluctantly, I packed up my equipment and headed back to my car, as the light was beginning to fade. I left with the overall impression of how colourful the lichens had been on the rocks there – quite a contrast to the dull, overcast grey day, but it was in fact those very conditions that enabled the lichens to be so vibrant.
Many thanks to John Douglass for his help in identifying some of the lichens in the photos on this blog.