Wessex Group: Walker’s Hill, Alton Barnes, Wiltshire

HomeEventsWessex Group: Walker’s Hill, Alton Barnes, Wiltshire

19 February 2023

Meeting report

After the past few months of quite appallingly wet winter weather, sunshine and mild temperatures were the order of the day for our meeting at Walker’s Hill, an exposed chalk escarpment rising dramatically from the dull arable fields of the Pewsey Vale. We were pleased to welcome several new members, including one under the age of 20!

Hidden from the view of most visitors to this site, we dived down into an area of former quarrying and archaeological forms. Not only was it out of the breeze that had swept the car park, but the closely grazed unimproved chalk grassland slopes face south. This rich area kept us occupied for a couple of hours, with many typical chalk grassland species being uncovered, together with some uncommon ones. Pete Flood found some nice Rhynchostegium megapolitanum (new for v.c. 7), and there was much Entodon concinnus, Microbryum curvicollum and Weissia brachycarpa var. obliqua (most of it stubbornly refusing to show us its peristome, or lack of). Seligeria calycina was winkled out of hiding in a rabbit burrow and there was plenty of Dicranella howei, new to some. Flexitrichum gracile was another new species for N. Wiltshire.

Sharon had suggested that the habitat (and timing) might lead us to Bryum torquescens, which looks rather like B. capillare growing on soil. There was a lot of what was probably fruiting B. radiculosum, an altogether smaller plant, but it was Rafik who spotted the first patch of B. torquescens, also needed for v.c. 7. After admiring and photographing it, we moved on uphill. As we walked up a well-used track, we spotted the massed capsules of a magnificent patch of B. torquescens on an ant-hill. That photo, artistically composed by Jonathan, made it into the Twittersphere.

Onward and upward, our destination a dense field of old ant-hills on the upper slope of the hill. We were hunting for Rhodobryum roseum, known from this locality, and we were not disappointed. Again, it was a new moss to most of the newer members.

Finally, we headed to the top of the hill where a series of gorse patches indicated a clay-with-flints cap and more acidic soils. Some areas also had sarsen stones, in this part of the world often providing the only habitat for Grimmia trichophylla. However, they were very exposed and supported very little, although Rafik was delighted to find some Syntrichia papillosa on the lee side of one. Acid soil around the sarsens offered Polytrichum juniperinum and P. piliferum, Ceratodon purpureus and some substantial patches of Brachythecium albicans. In the final gorse patch the tiny and enigmatic Acaulon muticum was admired on several ant-hills. It is a rare species in Wiltshire!

All in all, it was an excellent day in stunning surroundings. If only all field meetings had that kind of weather. Many thanks to everyone for attending and contributing knowledge and enthusiasm.

Sharon Pilkington

Meeting details

Leader: Sharon Pilkington

The extensive downland flank of Pewsey Downs National Nature Reserve supports rich and close-grazed unimproved chalk grassland. A visit in 2020 found Weissia sterilis, Pottiopsis caespitosa and Dicranella howei on the lower slopes. Upslope, a large population of Rhodobryum roseum is on the many old ant-hills and a clay-with-flints cap supports Acaulon muticum and Brachythecium albicans. What else can we find in this impressive site?

Meet at Pewsey Downs Car Park (free) at SU115637, just off the road between Alton Barnes and Lockeridge. This car park fills up quickly at the weekend, so we’ll meet at 10.00 instead of the usual 10.30.

Please remember to book your place with Sharon Pilkington sharon.pilkington1(at)btinternet.com


Walker’s Hill, Alton Barnes, Wiltshire SU115637