Loch Awe: small islands and curiosities
This islanded loch (NC2415) is a familiar sight for travellers on the road between Ledmore Junction and Inchnadamph (photo 1, 2012). It is a frequent stopping-off place for whooper swans in the winter and a favourite amongst fishermen, after brown trout and perhaps the occasional salmon which has made its way up the River Loanan.
It is also the site of an old record of grass-of-parnassus, made by Archibald Gray back in 1886, and not seen since, so far as we are aware. We were checking local records of this lovely plant, and on 23rd August 2020, we extended our search to the eastern bank of Loch Awe. We worked south from where the boats are beached, for about a kilometre, to a point where ribs of the rusty-coloured Fucoid Beds outcrop on the water’s edge.
A narrow marginal strip of grassland showed signs of base-enrichment, such as the distinctive palmate leaves of globe-flower Trollius europaeus, together with other indicators, for example fairy flax Linum catharticum and lesser clubmoss Selaginella selaginoides, but no grass-of-parnassus. One of us (Ian) had visited all the wooded islands on 3rd August 2012, but this species was not found on that occasion.
However, the visit was not without interest, since we did manage to get onto two of the smaller tree-less islands just off-shore, which were not accessed in 2012. We paddled over to the northern one (NC24661527), which is more substantial, with a raised bouldery centre clothed in bracken (photo 2). In half an hour we logged some 58 species of plants, noteworthy amongst which were the locally abundant, trailing, reddish stems and ovoid, shiny, leaves of bugle Ajuga reptans, amongst meadowsweet and wood-sage (photo 3). This blue-flowered member of the dead-nettle family is found on most of the islands in Loch Awe, but is otherwise confined locally to scattered sites behind Inchnadamph.
At the northern end of the island, Gwen spotted some small misshapen leaves on the bugle, a sample of which was collected (photo 4). The lower sides of these leaves, viewed later under a stereo-microscope, were found to be covered with tiny transparent blisters with yellow centres (photo 5). They were passed to Bruce Ing, the Rhue mycologist, who told us they were infected by an unusual micro-fungus called Synchytrium aureum, not previously recorded from West Sutherland. It belongs to a phylum known as the Chytridiomycota, parasites of higher plants, algae, other fungi, insects and microscopic animals such as rotifers, the most notorious member of the group being Synchytrium endobioticum, which causes potato wart disease.
The southern island (NC24691516) is smaller, about 25m long, and lower, with a scatter of boulders embedded in a grassy sward at its centre (photo 6, 2012). After the dry summer of 2020, the water level in the loch was low, and this island was easily reached over a causeway of large rocks. We did wonder if it was a man-made crannog, but archaeologists think that other islands in this loch are better candidates.
Its listing did not take quite as long, but we still mustered some 46 species of higher plants, including, once again, frequent bugle. Gwen noticed another oddity, a curiously distorted flowering head on a grass, possibly a bent, Agrostis sp., which appeared to be sprouting leaves (photo 7). This condition, known as phyllanthy, is sometimes caused by mites, but microscopic examination revealed none. Bruce suggested that the condition may, alternatively, have been the result of a viral infection.
It only goes to show that there is always something new to find!
Ian M. Evans and Gwen Richards