Bog pimpernel at Balchladich
The early afternoon of Sunday 30th August 2020 was delightful, with late summer sunshine and a light breeze to keep midges at bay. We had been searching the beach at Balchladich (photo 1) for a small sprawling annual called Ray’s knotgrass Polygonum oxyspermum ssp. raii, found there in late July 2017, by Ian Strachan, the Westerness botanist, and only once before in Assynt. We did find some skinny knotgrasses, but not that one, which has large, brown, shiny fruits.
Thwarted, we thought that we might treat ourselves and Jess to a walk along the cliffs north of the beach, with views over some of the best rock pools on our coast and, beyond them, a calm blue sea perfect for whale-watching, although none were seen by us (David and Avril Haines were more fortunate up by the Lighthouse). Along the way, we were looking out for one of Assynt’s rarest plants, bog pimpernel Lysimachia tenella. It is known from a small area alongside a burn on the cliff-tops (NC023306, photo 2), where Gwen had found its wintergreen leaves on the previous Boxing Day (see article posted on 21stFebruary 2020).
We were rewarded by a few late flowers tucked under the north-facing bank of the burn (photos 3-4). They were accompanied by the flowers of another ‘tiny’, pale butterwort Pinguicula lusitanica (photo 5). While one of us took close-ups, the other walked up the burn to see how far the bog pimpernel at Balchladich extended (photo 6).
Rather to our surprise, its creeping stems, with tiny, heart-shaped, paired leaves, are locally abundant in bog-moss Sphagnumspp. beside the burn (photo 7), and also around the small boggy pool from which the burn originates (photo 8). In the latter area it is competing with the much larger bogbean Menyanthes trifoliata and bog pondweed Potamogeton polygonifolius.
Bog pimpernel peters out a little further up the hill, beside a feeder for the boggy pool, but continues down the burn, in the opposite direction, below the deeply rutted track, to the edge of the cliffs, extending over a total length of some 60m. There is a small patch just below the track some 50m south-east, towards the beach (NC023305), but so far it has not been found anywhere else in the vicinity, or Assynt as a whole. We do not know why.
The Flora of Assynt (2002, p.100) does mention another record of bog pimpernel, ‘in 1981 near the mouth of the River Loanan’ (NC2421), made in the course of an extensive survey of the vegetation of local rivers. However, it has recently been noticed that the distinguished botanist, N.T.H. Holmes, who carried out that survey, apparently had a complete blind spot for a look-alike, New Zealand willowherb Epilobium brunnescens. This is widespread in Assynt, and elsewhere, yet he never mentioned it, so that record of bog pimpernel is now discounted. We can sympathise; one of us made the same mistake back in 2013, on spotting some tiny, paired leaves beside a small burn on the south side of Handa Island, but he was saved by later finding flowers.
Ian M. Evans and Gwen Richards