Nick Clooney, who manages the Tree Nursery off the Field Carpark at Little Assynt, is an experienced naturalist, with a keen eye, especially for plants. On 30th May, he sent us a series of photos of large numbers of the fern adder’s-tongue Ophioglossum vulgatum which he had found that day in a ‘dried -out muddy hollow’ (photo 1) not far from the Nursery (NC148248).
This is a curiosity amongst ferns, with a single entire frond up to 20cm tall, but often less. From the centre of the frond arises a stalked spike that bears 10-40 pairs of slit-like sporangia, green at first (photo 2), but maturing to a rusty brown.
The species is most often found in short grassland, often with light bracken cover, and it has been recorded locally from some 18 tetrads, many of them coastal. It has a much smaller and rarer relative with paired fronds, small adder’s-tongue O. azoricum, recorded in Assynt from just five tetrads, all coastal.
Re-visit
Gwen and I visited the site with Nick on 2nd June (photo 3) and were very surprised, both by the habitat and the sheer number of plants. There were over 200 in a small patch of silty mud (photo 4), on the bottom of a shallow pool that dried out earlier in the year.
Companions included shoreweed Littorella uniflora and lesser spearwort Ranunculus flammula, both of which often occur in shallow water that may dry out, usually on the edges of lochs. We have no idea why adder’s-tongue has occurred in such abundance at this site.
A relative
Adder’s-tongues have a relative that also occurs in Assynt, the equally inconspicuous, but somewhat more widespread, small fern moonwort Botrychium lunaria, which has a very attractive divided frond and much-branched spike (photo 5, at another site).
It is worth recording that, on 30th May, Nick had found two plants of moonwort not far away, on a south-facing earthy mound (NC148247) and, coincidentally, Gwen found at least twelve plants on the northern verge of the old road (NC150247) on 1st June. Much of the wildlife interest of this area relates to the fact that glacial sands and gravels were extensively quarried here many years ago, and patches of shallow sandy soil still occur in places.
Ian Evans and Gwen Richards