SBRS field meeting. Wednesday 17 April, 2024
I have two strong images of Nap Wood lodged in my memory from a trip led by Tom Ottley in 2015. The first, a winding stream in dappled spring light edged by luxurious cushions of woodland mosses including my first encounter with Dicranum majus. The second, trudging back uphill with Tom, David, Jacqui and Jackie with Jackie’s little Jack Russell darting ahead through brambly undergrowth.
Jacqui and I didn’t find this magical spot with Dicranum majus on our recce a week before this field meeting. Down by the main stream we didn’t find our target species, the beautiful leafy liverwort Handsome Woollywort Trichocolea tomentella, either. In 2015 three colonies of Trichocolea were found in different sections of the stream so it was frustrating not to find it, even with accurate grid references to guide us.
I mentioned to Sim that we hadn’t re-located the liverwort and he said, “Dave Bangs will find it, he has a nose for Trichocolea“. Sim was right. After lunch and slightly giving up hope, Ben, Sim and Dave disappeared for some time down a steep gill when eventually Ben phoned to say that Dave had located some Woollywort. Some of us scrambled across, leaving the rest of the group up to their knees in a large flush where Jacqui, in charge of recording the ferns and flowering plants, pointed out Marsh Valerian Valeriana dioica with white flowers just emerging, four plants of flowering Coralroot Cardamine bulbifera and an extensive glinting crust of Shining Hookeria Hookeria lucens. We found common Sphagnum auriculatum and Sphagnum palustre here but not the Sphagnum flexuosum found in 2015.
The Trichocolea was in a perilous position, hanging high above the stream at the edge of a flush. It could be washed away at any time. Above it and more secure for now was a mass of Riccardia multifida, the rarer of two similar species, this one has bulging marginal cells on its thalli. There were a few threads of Heterocladium which we have determined as H. heteropterum although it is a bit small for that species but not small enough to be H. flaccidum! Both were found in 2015. On a sandstone rock under the flush were a few tiny leaves of Fissidens pusillus.
Before all this post-lunch stream-side excitement there was a long walk along a well trodden path.
A long holloway leads from the entrance to the wood east towards the stream. The steep banks were a familiar rich patchwork of woodland mosses. The woodland floor around the path was largely bare of bryophytes and flowering plants so we squelched along the muddy path admiring Polytrichum formosum, Dicranum scoparium, Thuidium tamariscinum and Dicranella heteromalla, all conveniently at eye height on the sheltered banks. Leafy liverworts included brownish fringes of Diplophyllum albicans and the bright green Lepidozia reptans with its distinctive right-angled branching grew in extensive sheets.
A few trees were checked for epiphytes and a lone cushion of Orthotrichum pulchellum with pixie hat capsule lids, Metzgeria violaceae tipped with gemmae and Zygodon conoideus, all tiny compared to the luxurious bryophytes on the holloway.
One cushion of pale Leucobryum on the bank had long, soft leaves. We spotted a few colonies of Leucobryum on Sweet Chestnut coppice stools and these all had the stubbly, doormat appearance of Leucobryum albidum, confirmed microscopically. I’m still undecided about the one on the bank.
Just off the path, quite a large open area of dry, sandy earth was covered with Campylopus introflexus. This invasive species was not recorded in 2015 so it may have arrived after that visit. We only found a tiny bit of scruffy Campylopus pyriformis on a stump. This was recorded in 2015.
As we descended further into the humid wood Pseudoscleropodium purum, Pellia epiphylla, Calypogeia arguta and Calypogeia fissa appeared on shaded banks by the path.
With still a way to go to the stream the path petered out and we had a choice of deer tracks to follow, all leading to different bits of the gill and none of them easy. Brambles, fallen trees, steep banks and muddy flushes all got in our way on the descent.
There were plenty of excuses to stop for a breather with the lovely worms of Plagiothecium undulatum to admire by the path.
We arrived at an area of wet woodland by the stream where Cratoneuron filicinum, Brachythecium rivulare and Oxyrhynchium hians grew brightly in the wet. A large Ash hanging onto the stream bank was wrapped with Homalia trichomanoides at its base. Along the stream bank, Conocephalum conicum, another sign of base rich conditions, covered areas of vertical bank. Pellia endiviifolia was identifiable by its frilly margins by the stream but further up the banks where the ground was more acidic Pellia epiphylla was the dominant thallose liverwort.
The stream meanders meant it was hard to know which side we were on. Alder and Ash, almost marooned in a hairpin bend, had robust Isothecium alopecuroides at their bases.
On the banks of a side stream Cirriphyllum piliferum spread its pointed branches and Eurhynchium striatum grew abundantly. One rotting stump had a dowdy cover of Plagiothecium curvifolium with its lop-sided leaves.
We ate lunch high above the stream before heading back down to the Valerian and Woollywort flushes.
After much clambering about it was time to start back but with no clear paths we zig-zagged around looking for the easiest route, our meandering resulting in finding a bank of Hay-scented Fern Dryopteris aemula in a holloway overgrown in parts with Holly. On the recce Jacqui and I found Pogonatum aloides with bright white capsules on earth on an upturned stump near this spot but on both days we failed to spot the Dicranum majus.
Just before we joined a clear path most of the group disappeared down to the stream to look at Large Bitter-cress Cardamine amara with its distinctive purple anthers. On drier ground a large Ash tree had a long line of Zygodon stirtonii with thick excurrent nerve down the trunk. Sim and Dave found Barnacle Lichen Thelotrema lepadinum, an ancient woodland indicator, on Hazel and Ben collected the beard lichen Usnea cornuta and crustose lichen Lecanactis abietina on Oak.
We ran out of time and didn’t check a flush where the path crossed the stream to see if Marsh Violet and Sphagnum fimbriatum were still there.
There are still good bits of Nap wood that we didn’t get to on this visit and a few species that we didn’t re-find. We did add some new species including Ctenidium molluscum, Riccardia multifida and Pogonatum aloides. It would be worth visiting again before concluding that the missed species have disappeared from the wood.
I didn’t take any good photos of the Trichocolea and still need to get down to drawing this intricate plant. It will be a challenge as I only have this dusty herbarium specimen to hand!
[Here at last is a drawing of the dusty specimen.]
Sussex Bryophytes 