Iet Wen Quarry, Glandwr

The working quarry at Garn Wen is obvious as one drives south from Crymych along the Pembrokeshire / Carmarthenshire border, but there are three smaller, disused quarries within a short distance of each other to the north of there. What's striking about these is how different from one another they are. The old slate quarry on the hill at Foel Dyrch is typically dry and acidic, with Ditrichum lineare and Grimmia donniana amongst the notable species. A few hundred metres to the east and lower down the flank of the hill, the narrowly incised shale quarry at Foel is damp and shaded, with Platyhypnidium lusitanicum, Philonotis arnellii amongst a luxuriant growth of commoner species.

I'd looked at the third of the trio, the dolerite quarry at Ietwen, once before but thought it worth another crack. Fortunately it hadn't changed much - it's still vegetating naturally, and peregrines and ravens were much in evidence.

The dolerite introduces some base-richness to the flora, and this is the only site that I know in the county where Encalypta streptocarpa grows on a cliff rather than a lime-mortared wall - it's patchily abundant in the north-west corner. Aloina aloides is in places on soil amongst boulders on the quarry floor with Bryoerythrophyllum recurvirostrum and some Trichostomum brachydontium. There is also an abundance of Weissia, mostly W. brachycarpa var. obliqua but also W. controversa var. controversa and perhaps some W. rutilans on the damp floor with Archidium and some Bryoerythrophyllum ferruginascens.

Encalypta streptocarpa with maidenhair spleenwort

Weissia brachycarpa var. obliqua

Perhaps the other interesting feature of the quarry is the occurrence on rock of species which are more typically epiphytic. There is a tiny amount of Colura calyptrifolia on the north-facing igneous cliff, whilst Cryphaea heteromalla grows through Orthotrichum cupulatum on one rock. A small amount of what seems to be Zygodon rupestris may need double checking, as I haven't found gemmae yet. More typical saxicolous mosses here include Ptychomitrium polyphyllum, Grimmia trichopylla, Schistidium crassipilum and some Hedwigia stellata.

There were two additions to the Rare Bryophyte Register which I'm slowly drafting - Dicranella subulata which was fruiting in small quantity in one corner of the quarry, and Ditrichum pusillum which was amongst Bryoerythrophyllum recurvirostrum on the damp edge of the entrance track. I've now found four track-edge sites for the Ditrichum in north Pembs in as many months.

Saxicolous Colura calyptrifolia

Cryphaea heteromalla with Orthotrichum cupulatum