Dumfriesshire Botany Group at Dalveen Pass, 8th September 2024
Four of the group met on a warm day in the Dalveen Pass to explore some squares that had few records in the system. The Dalveen Pass is one of three principle routes through the Lowther Hills linking Carron Bridge with Crawford. This is quite a dramatic landscape deepened into a classic U shape by ice and probably by meltwater as the icesheets melted.
The two target squares of NS9006 and NS8906 rise steeply from the A702 and had only five records and 13 records respectively in the system most made by Olga Stewart in the 1970s.However as we shall see earlier botanists had almost certainly been here. The very steep slopes have rocky outcrops and scree and hill burns occupy some rocky linns.
We started by working our way up the Capel Cleuch into quite impressive rocky country where the Cleuch flows through a Linn. Flushing along the lower slopes had plenty of the golden orange moss Palustriella indicating at least moderate base rich conditions. So it was no surprise to be finding Glaucous Sedge Carex flacca, Flea Sedge Carex pulicaris and Carnation Sedge Carex panicea in good quantity alongside Lesser Clubmoss Selaginella selaginoides, Fairy Flax Linum catharticum and Common Butterwort Pinguicula vulgaris, though the latter is pretty happy in acid flushes as well.
We soon established that Mossy Saxifrage Saxifraga hypnoides was very frequent wherever water was dripping or seeping. It was already recorded in other parts of the Dalveen which looks like a local stronghold for this species in this part of the Lowthers.
More significant perhaps was finding small stands of Wilson’s Filmy-fern Hymenophyllum wilsonii on a number of rocks especially on the south side of the Linn. This looks like the first record for this in NS90 since the 1950s. There is a record by Humphrey Milne-Redhead, the then recorder, for the NS90 hectad in 1958 though he does not say where he found it. It has been found elsewhere in the Dalveen recently. As a tiny delicate fern it may well have prospered in this very wet summer!
The rocks had lots of Goldenrod Solidago virgaurea some still in flower though most now with fluffy seed heads. The same was true for a number of plants of Hiracium and a visit will need to be made next year in June or July to see what species are present. Fortunately one species could be identified from leaves and the fruit head. This was Rough-leaved Hawkweed Hieracium prenanthoides a species I was happy to find as it was last recorded in Dumfriesshire in 1984 and in the Dalveen in 1975. It is identifiable as one of few hawkweeds with amplexicaul leaves i.e. leaves that clasp the stem.
It was really pleasing to find three spleenworts on the rocks too. The tetraploid Maidenhair Spleenwort Asplenium trichomanes ssp quadrivalens was the most abundant. Its less common and more delicate cousin Asplenium trichomanes ssp trichomanes was also present. It is a diploid and favours more acid rocks. Most interestingly were several clumps of Green Spleenwort Asplenium viride. This is a specialist of basic rocks and is very uncommon in the Southern Uplands. As with the Filmy-fern there is a record in NS90 for this species from 1958 by Humphrey Milne-Redhead. Perhaps he visited this very location.
After reaching a water fall at the junction of the Capel Cleuch and Wee Capel Cleuch we had lunch. We then headed up slope out of the Linn. On the top of Greentrough Head we passed into the NS8906 monad and started recording the very limited heath and acid grassland community on the tops of the hills. Other than Viviparous Fescue Festuca vivipara there was nothing noteworthy and no depth of peat to support a blanket bog community. The party then split with one half heading down the fence line of Petty Lung Hill while the other half worked their way down the March Linn.
The rocks in the March Linn were less calcareous than the Capel Cleuch Linn which was shown up by the extent of Parsley Fern Crytogramma crispa that had been absent from the Capel Cleuch. There was also plenty of it in scree patches right down near road level. The rocks still supported Mossy Saxifrage Saxifraga hypnoides and Wilson’s Filmy-fern in several spots. Fir Clubmoss Huperzia selago was a nice addition. It is not very common in the Lowther Hills. Lower down in a slightly more flushed situation the best find was Knotted Pearlwort Sagina nodosa. Without flowers the slender stems and leaves are hard to spot at this time of year. It has only been recorded once before in the Dalveen Pass.
The A702 and the Carron Water fall within the NS8906 square. So once down at the bottom of the slope we explored the road verge. There were a number of normally coastal species including Lesser Sea-spurrey Spergularia marina and Spear-leaved Orache Atriplex prostrata. They were in the zone where winter salt spreading has altered the conditions and were joined there by masses of Marsh Cudweed Gnaphalium uliginosum, Fat-hen Chenopodium album, both Early Hair-grass Aira praecox and Silver Hair-grass Aira caryophylla and the rather heavy headed Northern Dock Rumex longifolius.
We finally explored part of the flood plain of the Carron Water. In the valley bottom this has a braided channel with a number of side and back channels. In these we saw bright patches of Hybrid Monkeyflower Erythrnathe x robertsii, Marsh Horsetail Equisetum palustre, Common Spike-rush Eleocharis palustris and Hybrid Woundwort Stachys x ambigua. On the wider flood plain there were a number of sedges including Brown Sedge Carex disticha and Hairy Sedge Carex hirta.
The total number of records made in the two squares was 271.
Chris Miles
BSBI county recorder for Dumfriesshire VC73 – see bsbi.org/dumfriesshire
