Dumfriesshire Botany Group at Loch Urr, 14th August 2019
It was a cool damp windy day that promised to brighten up but which in fact by the end of the afternoon deteriorated. Eight of us met on the Kirkcudbright side of the line and managed to park on the verge. We walked from here into square NX7585 at the north west end of the Loch, though we largely ignored the wet acid grassland on the fields to the north and spent most of our time exploring between the road and the loch shore.
On the slope down to the loch the wet grassland was a mosaic with small patches of mire. The grassland was dominated by acid grassland species like Purple Moor-grass Molinia caerulea, Wavy Hair-grass Deschampsia flexuosa and Brown Bent Agrostis vinealis along with rushes like Sharp-flowered Rush Juncus acutiformis and Heath Rush Juncus squarrosus. Typical herbs in this rather western location like Whorled Caraway Carum verticillatum and Skullcap Scutellaria galericulata were to be expected. On the areas with deeper peat, which appeared more palatable as they were more grazed down, typical mire species included Heather Calluna vulgaris, Blaeberry Vaccinium myrtillus, Cranberry Vaccinium oxycoccus, Deergrass Trichophorum germanicum and Bog Asphodel Narthecium ossifragum. On one patch of bog we saw Cruet Collar-moss Splachnum ampullaceum growing on an old patch of dung. This odd moss only grows on dung and its expanded capsule base attracts the flies needed to get spores to the next patch!
We followed a burn running into the loch and as the gradient levelled out the ground became wetter. Given the recent high rainfall the loch level was extremely high and had inundated an area of willow carr that though clearly permanently wet was flooded on the day we visited. This made exploration of the area difficult and precarious. However the willow carr had as good growth of Bay Willow Salix pentandra with its dark green, hairless, shiny leaves. The water channels, being largely out of reach of grazing stock had a nicely developed flora including Bogbean Menyanthes trifoliate, Water horsetail Equisetum fluviatile and Marsh Cinquefoil Comarum palustre. On slightly higher ground there was Bog Myrtle Myrica gale.
As the burn entered the loch it was evident that the level of the water was going to frustrate searches for many of the marginal and submerged aquatics we had hoped to find. Loch Urr lying right at the edge of Dumfriesshire, in fact the county boundary with Kirkcudbrightshire runs through the loch, has species not found in many other places in the county. Water Lobelia Lobelia dortmana and Quillwort Isoetes lacustris are examples of submerged aquatics previously recorded but not seen due to the depth of the water. Neither did we see marginal plants like Small Water-pepper Persicaria minor or Lesser Water-parsnip Berula erecta. We were able to compare and contrast the leaves of the two native water lilies in the absence of flowers. This is a way of deciding if you are looking at yellow (Nuphar lutea) or white water lily (Nyphaea alba).
The nerves arise from near the base on White Water-lily and along the midrib in Yellow Water-lily as per the photo. As you can see both were present but we failed to see leaves of the hybrid between Yellow Water- lily and Least Water-lily Nuphar pumila which is also known from the Loch.
After lunch in a spot as much out of the wind as we could find we recorded in the next square NX7684 taking in more of the loch shore and then the roadside. We saw mostly more of the same species with the addition of Common Spike-rush Eleocharis palustris and Canadian Waterweed Elodea canadensis from the loch shore.
BSBI county recorder for Dumfriesshire VC73 – see bsbi.org/dumfriesshire