BBS SE Group field meeting, 25 September 2021
The area around Balcombe has been well surveyed in the past, with over 150 species recorded in TQ33A over many years including many rarities. It is a varied, undulating landscape with a host of wooded gills, sandstone rocks, lakes, reservoirs and old built structures. There is an ancient record for Antitrichia curtipendula, found by Mitten in 1849, which hasn’t been seen since and we don’t have a precise location to search for it in. More recently, Leucodon sciuroides was found in the churchyard by Frances Rose in 1975. I have searched for this with no luck but did find Gyroweisia tenuis on the church wall in 2019. There are damp sandstone rocks near the reservoir, that we weren’t able to reach on our walk, with Harpanthus scuttatus, Hookeria lucens, Heterocladium heperopterum and Herzogiella seligeri and those are just some of the mosses beginning with H.
Practical reasons for choosing to hold a field meeting at Balcombe were the large lay-by and a stop on the London to Brighton line. We hadn’t predicted a panic about fuel shortages with queues at any gas stations that still had stocks of diesel and petrol. On top of that, a shortage of train drivers meant that half the trains were cancelled so it was brilliant that a group of ten assembled, four on their first BBS field trip!
The first stop was a metal drain cover on the verge, covered with the shiny tips of Brachythecium rutabulum. A steep bank which bordered the churchyard had a nicely feathered and fruiting example of Kindbergia praelonga and Dicranella heteromalla was also bearing capsules. A bristly forest of the woodland moss Polytrichum formosum growing with soft, bright green Dicranum scoparium meant another clamber up the bank for a closer look and Mnium hornum grew in easier reach. We had seen a good selection of our most common and attractive mosses without leaving the car park!
We couldn’t leave the area without looking at tarmac mosses and found Didymodon luridus, D. insulanus and Bryum dichotomum with bright bulbils. Brad spotted some Syntrichia latifolia, a moss that favours damp habitats and is a new find for the tetrad.
Outside the rectory we added Silver-moss Bryum argenteum, a hardy little moss with a worldwide distribution. Joan said she has seen it on all five continents!
Along the top of a sandstone and brick wall there were cushions of Grimmia pulvinata and Tortula muralis, both fruiting, and scruffier patches of Syntrichia montana. Lime green curls of Homalothecium sericeum fanned across the side of the wall.
Around the corner and past the pub and village shop we left the road and joined the footpath. Sandstone rocks edging a garden were damp and mossy with Tortula marginata and Rhynchostegium confertum, the former was checked microscopically for its pale, thickened margin. The wavy leaves of Streblotrichum convolutum var. commutatum (=Barbula sardoa) grew in a small patch on soil.
The footpath crossed the top of a large field dropping away to the north, landscaped with Oak trees, planted to provide a pleasing vista for the large house at the edge of the village. A long ditch which may have once been a ha ha was behind barbed wire fence but where it turned a corner was accessible and we spent a while here, finding the lettuce-like liverwort Fossombronia pusilla. I had found it fruiting on the recce and it’s spores, checked microscopically had about 18 marginal spines, double checked and confirmed by Tom. The small thallose liverwort Riccardia chamedryfolia was checked and confirmed by James and there were a few shoots of Pseudephemerum nitidum.
There were plenty of large-celled leaves on bare earth in the rest of the field and we suspected Tortula truncata but it took us a while to find mature capsules to confirm.
Leaving the meadow we looked at some thin Hazel branches scattered with epiphytes. It seemed poor time management to spend so long on a spindly sapling and rotten gate post when a large wood lay ahead but this was the only place where we saw Orthotrichum lyellii and Cololejeunea minutissima (on the Hazel) and Campylopus introflexus and Dicranoweisia cirrata (on the gate post).
Just into the wood, patches of Atrichum undulatum were fruiting profusely on the woodland floor and Fissidens taxifolius with unbordered leaves and F. bryoides with bordered leaves and male buds in the leaf axils grew neatly on banks, Pseudotaxyphyllum elegans grew in silvery flattened shoots. Pohlia melanodon grew on wetter banks by a small rivulet.
On trees, Mousetail Isothecium myosuroides hugged the base of an Ash tree and Hypnum andoi was fruiting on a tree nearby. Jacqui found the little acrocarp Zygodon conoideus on a leaning Willow and Brad collected Z. viridissimus on a Field Maple.
Jacqui picked up a fallen branch with a lovely sample of Cryphaea heteromalla, showing its spiky sillhouette and unusual side-fruiting habit. A few shoots of shiny-tipped Cirriphyllum piliferum threaded through the forest floor. Another striking moss was a clump of Oxyrrhynchium hians with masses of capsules. I don’t think I’ve seen this common moss fruiting before but there are a few records for fruit in Sussex.
Brad, Colette and Matt ventured off the path to an Ash tree with Neckera complanata, Metzgeria violaceae and Homalothecium sericeum. N. complanata has not been recorded in this tetrad since 1948.
Back on the footpath the typical woodland bryophyte Tamarisk Moss Thuidium tamariscinum grew in a small but lush patch. Nearby were a few springy shoots of Stripe Moss Eurhynchium striatum and dark green Polytrichum formosum, fruiting on long stalks.
A deeply incised stream crossed the path, crammed with sandstone rocks coated in Chiloscyphos polyanthos to the exclusion of much else. The stream descended into dense Holly cover so we weren’t tempted to explore further downstream. Some sandstone rocks on the path had the tiny moss Fissidens pusillus, much of it fruiting.
We puzzled over some Metzgeria which was enveloping the branches of a Holly tree, along with Radula complanata. Joan took some home and found the thallus four or more cells wide and gemmae mostly on the thallus tip making it Metzgeria violaceae. I collected an unidentifiable sample but did find a thread of Fairy Beads Microlejeunea ulicina running through.
We were flagging by now and very pleased to reach the lake and a bright, scenic spot to eat lunch.
There wasn’t much to be found on the steep banks of the lake or on trees leaning across the water just lots of Dicranella heteromalla on sandy banks and Isothecium myosuroides on a tree base, but venturing to wet woodland nearby there was Brachythecium rivulare to add.
A grassy meadow only added Calliergonella cuspidata and more Tortula truncata on damp mole hills and we walked over more of it than intended as I lost the way!
It was a bit of a trudge along the lane to pay homage to a wonderful roof full of Hedwigia stellata. I’m sure there is more here now than when Tom showed me the colony in 2014 but don’t have a photo to compare it with.
Then it was a long walk back to Balcombe, too tired to check out some sandstone rocks hidden behind brambles. We didn’t miss much as they are shaded and dry. I only found Mnium hornum on the recce. The good rocks are further down the lane and innaccessible from footpaths.
We had seen 63 different bryophyte species on our walk but only added three new taxa to the tetrad list. Walk Wood had no previous bryophyte records so it was good to check out this unexplored area.
Sussex Bryophytes 
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