Clashnessie Falls: an August miscellany
Days out often acquire an agenda at odds with our intentions. Such was the case on 18th August 2019, when Gwen Richards, Pam Mackenzie and I visited Clashnessie (NC0530). Our purpose was to check out one of the five recorded sites in Assynt for bog orchid Hammarbya paludosa, below the Falls. Gwen and I had re-located it three days previously at a site north of Lock Stack (NC2845), which I had last visited some 25 years before, and, although it is tiny (photo 1), I thought we had a chance of finding it locally.
I had not personally seen the orchid at Clashnessie, where it was found by Margaret Macdonald in 1987 in some quantity ‘on gravelly sands by a rivulet…about three-quarters of the way in to the falls’. After referring afterwards to the detailed notes in my files, I think that the site may be on the eastern side of the river. We approached the Falls, which were an impressive sight after heavy rain (photo 2), by the path on the western side, and the stepping stones were awash, so the chances of finding it were stacked against us.
However, the day was not without interest. Shallows at the edge of the fast-running river (photo 3) contained flowering plants of pale butterwort Pinguicula lusitanica and the thread-like branches of lesser bladderwort Utricularia minor (photo 4). Amongst the latter I noticed a diamond-shaped aquatic insect which, on closer examination, proved to be an immature water scorpion Nepa cinerea (photo 5). We have only once before seen this waterbug in Assynt, at Achmelvich on 13th June 2016, when it was ‘new’ to the north-west Highlands.
Shortly afterwards, I gathered a sample of the lesser bladderwort and other vegetation from an insignificant-looking runnel in a long-abandoned area of former cultivation or ‘lazybeds’ (photo 6), to process for desmids. These microscopic green algae occur in a wide variety of exquisite forms, and are the special interest of an old friend down in Leicestershire, David Williamson. I sent the material to him, and some three weeks later he came back with a list of 19 species, and drawings of most of them.
He was, however, unable at the time to identify one particular species of Cosmarium, and sent drawings, photographs and slides to another desmid expert in The Netherlands, suspecting that it might be a species new to science. In the event, it proved to be a known, but very rare, species, Cosmarium corriense (photo 7), described new to the British Isles from a quarry on the Isle of Arran in 1894 and known otherwise from the Massif Central in France.
We then climbed up the western side of the Falls to the ridge at their top, which affords splendid views over the Bay (photos 8 and 9), and then continued a little further upstream. This took us to a place I had never previously visited. The ground to the west of the river is a delightful mosaic of dry and wet heath, with outcropping rock and basic flushes, encapsulating in a small area much of the variety of vegetation typical of our Lewisian gneiss and, happily, no longer heavily grazed. There is more ground to explore above some smaller upper falls (photo 10).
Back via the trees
On our way back to the road we left the track to look at some old trees beside the ruins of a house (photo 11, NC053304). One of them was the predictable elder Sambucus nigra, nearly always found in Assynt near habitation. The other was a huge, sprawling multi-stemmed willow (photo 12), with large, but fairly narrow leaves, dark green and shiny above, but with a felty covering of soft appressed hairs beneath (photos 13 and 14).
I took a sample home, which allowed me to identify it, after some puzzling, as broad-leaved osier Salix x smithiana, a hybrid between goat willow S. caprea and osier S. viminalis. This hybrid was once widely cultivated elsewhere for use in coarse basket work, but is only known otherwise from Assynt as a single tree at Inverkirkaig, which grew from a stake (source unknown) pushed into the ground as a gatepost some 80 years ago.
I later asked Roddie Kerr of Clashnessie about the ruined house and he informed me that it was on his croft, known as Duncan Callum’s house, and had not been occupied since the 1940s. From the size of its several trunks the broad-leaved osier may have been planted over a century ago.
So, no success with our search for the bog orchid, but nevertheless a great day out.