Further halophytes at Brackloch
In the summer of 2019 I posted a story on the salt-tolerant plants that occur along our roadsides, using silverweed and sea plantain as conspicuous examples, and also mentioning some smaller species.
On 20th September 2020 Gwen Richards and I dropped down to the roadside at Brackloch (NC115240) after having had an enjoyable day listing higher plants in the 1km square north from there to Loch Uidh nan Corp. The gritty gutter on the north-west side of the road (photo 1) housed a couple of ‘tinies’, of which I collected a sample for closer examination (photo 2).
One was sea pearlwort Sagina maritima, with ‘chubby’ leaves bearing tiny points, which we have now encountered several times in such habitats. The other was our first inland record for sea mouse-ear Cerastium diffusum, otherwise confined to sandy grassland near the sea. It is an annual with its floral parts in fours, as opposed to fives in its widespread perennial relative common mouse-ear C. vulgatum. Old leaves on the sea pearlwort bore black dots, the fruiting bodies of a tiny ascomycete fungus Mycosphaerella saginae. Bruce Ing, who kindly named it, says that it is rarely recorded, which is not altogether surprising.
I returned to the site a month later, on 22nd October, to take some photos, and had another look along the roadsides on both sides of the road. The north-western side produced a small, sprawling, grass, with finer leaves and smaller flowers than the ubiquitous annual meadow-grass Poa annua (photo 3). Again, a sample was collected, for later examination under the microscope, which makes measuring its parts possible.
This proved to be the less common of two sub-species of reflexed saltmarsh grass Puccinellia distans ssp. borealis. It was, until recently, thought to be restricted to wave-splashed rock platforms on the northern and eastern coasts of Scotland, but is now known to be extending its range along roadsides. It appears to be ‘new’ to Assynt.
Its much taller relative, P. distans distans, has spread north along the road network throughout eastern parts of England and Scotland, from coastal and inland saline habitats, since the 1970s. Andy Amphlett of Grantown-on-Spey, a regular visitor to Assynt, issued a circular in 2018 which helps us differentiate these two ‘invaders’. There is a 2013 record of this second sub-species from Knockan, the voucher specimen for which now requires checking.
Across the road and more halophytes at Brackloch
My car was parked at the entrance to the Brackloch side-road, and on my way back I took a look at the south-eastern verge, alongside a road sign (photo 4). Many of the usual roadside species were present, including more sea pearlwort.
What caught my eye was a compact plant with shiny heart-shaped leaves (photo 5), a small sample of which was collected and later photographed close-up (photo 6). This was chaffweed Lysimachia minima, a tiny annual bearing fleshy leaves, with a narrow dark band around the edge of the undersides, and attractive, reddish, spherical fruits with a tiny spike on top. It was first recorded in Assynt by Pat and I in 1991, just above the high tide mark on the cliffs at Rubh’an Dunain, Culkein Stoer (it appears in the Flora of Assynt under its former name of Anagallis minima). Previously considered, again, to be exclusively coastal in the north-west, it is also now turning up along roadsides. Despite its delicate appearance, its seeds are presumably transported in mud on vehicle tyres, like those of other roadside halophytes at Brackloch, and beyond.
Ian M. Evans (words and photos)