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  • Writer's pictureSim Elliott

Rock Wood SSSI, Heron's Ghyll, East Sussex: Bryophytes, Lichen, Ferns & Fungi. 13.10.23

Rock Wood is an SSSI noted for its oceanic bryophytes and it can be reached by the 29 Bus from Brighton; alight at Hendall Gate Farm stop. Regency 29 - Brighton-Tunbridge Wells and Heathfield | Brighton & Hove Buses. It is a 75 min journey from Brighton to and there is a bus every 30 minutes. Tell the driver you want to get off at that stop, as very few people get off at that stop and the drivers need quite a lot of notice.

From the bus stop, you can either walk along the path (track) that leads to Hendall Manor Fam, then take the path into Rock Wood. Alternatively you can walk up to the southern edge of Furnace Wood, where there is another footpath to Hendall Manor Farm, which runs on the south side of the Furnace Wood fence. This is the path that I took, as I wanted to look at what I initially thought was a pond in the South-East corner of Furnace Wood. However the footpath is not signed from the road, but I have included below a photo of the point on the road where the path starts. To get to the southern edge of Furnace Wood you need to walk up the A22 (going north) for about 750m, but there is no footpath, and in places no verge to walk on, so caution needs to be taken.

This the turning off the A2 to the path south of the Furnace Wood boundary fence

This is the style until the field south of Durnace Wood

Map of the Rock Wood SSSI

All sections of text in italics are quotations, sources sited.

The photographs are presented in the chronological order of my walk.

I am only an amateur naturalist; thus all identifications are provisional; if you note a mistake in identification please feel free to tell me. If you want to contact me about any aspect of this blog, email me at simeon[underscore]elliott[at]gmail[dot]com.

SSSI citation

Reasons for Notification: Rock Wood is a small ancient woodland lying on Tunbridge Wells sandstone and Wadhurst Clay. A number of different broadleaved woodland types are represented, and there has been some underplanting with conifers. A small stream and its tributary have cut through the sandstone in places creating steep sided ghylls which contain various uncommon ‘Atlantic’ bryophytes (mosses and liverworts) and ferns. The western part of the site is predominantly hornbeam Carpinus betulus coppice, with scattered oak Quercus robur standards and some coppiced hazel Corylus avellana. An ancient bank with hornbeam coppice marks the eastern edge of this type beyond which oak is the dominant tree, with holly Ilex aquifolium, and coppiced birch Betula spp and hazel. In the south-east beech Fagus sylvatica is co-dominant with oak. Ash Fraxinus excelsior is also present, while coppiced alder woodland occurs along the main stream. In the north spruce Picea sp., Douglas fir Pseudotsuga menziesii, Scots pine Pinus sylvestris have been planted underneath the mixed broadleaved canopy. Ground flora is sparse under the hornbeam coppice, beech and dense holly while under the oak and hornbeam bramble Rubus fruticosus, ground ivy Glechoma hederacea, wood-sorrel Oxalis acetosella and dog’s mercury Mercurialis perennis are found. Wild daffodil Narcissus pseudonarcissus and broad-leaved helleborine Epipactis helleborine are also recorded from Rock Wood. The ghylls feature a small waterfall which has developed where the smaller stream flows over one of several sandstone outcrops occurring throughout the wood. These ghylls have a moist, mild microclimate which is suitable for a number of ‘Atlantic’ plant species uncommon in south-east England. These include the mosses Tetraphis browniana and Diphyscium foliosum and the liverwort Marsupella emarginata. Hay- scented buckler fern Dryopteris aemula and Tunbridge filmy fern Hymenophyllum tunbrigense are also present on this site. 1003127 (

South East of Furnace Wood

Furnace Wood may be a private wood but the south-east corner has open access. On the OS map there appear to be ponds in this corner; but these ponds are in fact bogs, which much sphagnum moss. Care needs to be taken as the forest floor when covered in fallen leaves looks like firm ground but part of it is bog into which you can sink up to your knees

Probably Common Smoothcap, Atrichum undulatum

Common Tamarisk-Moss, Thuidium tamariscinum

Possibly Grey Sedge, Carex divulsa

Path (not an official footpath) to the south-east corner of Furnace Wood

Probably Horn Calcareous Moss, Mnium hornum

Probably Common Feather-Moss, Kindbergia praelonga

Probably Spiky Bog-moss, Sphagnum squarrosum

Probably Fox-tail Feather-Moss, Thamnobryum alopecurum

Possibly Fringed Bogmoss, Sphagnum fimbriatum

A mossy Beech, Fagus sylvatica

Mossy silver Birch

Probably Common Feather-Moss, Kindbergia praelonga

Sphagnum bog

Possibly Mealy Forked Cladonia, Cladonia scabriuscula and Cypress-leaved Plait-Moss, Hypnum cupressiforme on log

Cypress-leaved Plait-Moss, Hypnum cupressiforme

Black Stone Flower, Parmotrema perlatum with Cypress-leaved Plait-Moss

Broad Buckler-Fern, Dryopteris dilatata

Possibly Trumpet Chanterelle, Craterellus tubaeformis with sphagnum sp. moss

Polypody fern, Polypdoum, probably Intermediate Polypody, Polypodium interjectum

Growing epiphytically on probably Goat Willow, Salix caprea

Probably Cypress-leaved Plait-Moss, Hypnum cupressiforme, with tiny grey fungus

Lichens and Mosses on rocks between Hendall Manor Farm and the entrance to Rock Wood

A beautiful rock covered in lichens and bryophytes. This rock is one of several around the base of a Hawthorne Tree in a field between Hendall Manon Farm and Rock Wood

but the crustose lichens on it (Lichen campestris, Lecidella stigmatea) I do not typically see on sandstones of the Tunbridge Wells Sand Formation (see BGS Lexicon of Named Rock Units - Result Details) in High Weald ghyll woods. It is possible that this range of crustose lichens is growing on these rocks because they have continuous sunlight. Most sandstone rocks in high weald are in woods with trees which provide a high level of shade. Alternatively these rocks are not Sandstone but imported rocks associated with landscape work carried out in the past.

The rocks

Some of the lichens and bryophytes on on this rock

Lecanora campestris

Possibly Rock Disk Lichen, Lecidella stigmatea

Common Goldspeck, Candelariella vitellina

Grey-cushioned Grimmia, Grimmia pulvinata

Rough-stalked Feather-moss, Brachythecium rutabulum

A Cladonia sp lichen

Possibly, Silvery Bryum, Bryum argenteum

Inside Rock Woods

The entrance into the woods was hidden between a Sycamore and a Chestnut - both in autumn fruit; behind these trees was a Holly in full berry

Sweet Chestnut, Castanea sativa

European Holly, Ilex aquifolium

Sycamore, Acer pseudoplatanus

On entering the wood the typically and stunning ambience of Ardingly sandstone ghyll woods was apparent - trees (oak, birch, yew, holly) growing on sandstone

And the rocks were covered in bryophytes and lichens, as is typical in high weald ghyll woods, which have maintained an oceanic microclimate similar to the former Atlantic conditions of the south east 5000 years ago.

Probably Silky Forklet-Moss, Dicranella heteromalla

Probably Horn Calcareous Moss, Mnium hornum

Forked Veilwort, Metzgeria furcata

Beech, Fagus sylvatica

English Yew, Taxus baccata

Probably Cypress-leaved Plait-Moss, Hypnum cupressiforme

This area of ground covered by dry recently-fallen leaves, surrounded by slabs of Ardingly sandstone, turned out to be a bog, into which I sunk up to me knees.

Toothed Plagiothecium Moss, Plagiothecium denticulatum

Possibly Clustered Feather-Moss, Rhynchostegium confertum

Oak Pin fungi, Cudoniella acicularis

Beefsteak Polypore, Fistulina hepatica

Broad Buckler-Fern, Dryopteris dilatata

Probably Honeycomb Coral Slime Mold, Ceratiomyxa fruticulosa

Male Fern, Dryopteris filix-mas

Possibly Snakewort, Conocephalum salebrosum

The ghyll (Hero's Ghyll) rises from a spring in Ashdown Forest and is a tributary of the River Ouse

A Bonnet, Mycena sp., growing on a fallen leaf

The forest floor covered in Broad Buckler, Male and Scaly Male ferns

A Feather Moss sp., Order Hypnales

Common Pocket-Moss, Fissidens taxifolius

A dry tributary stream to the main ghyll

Probably Elegant Silk-Moss, Pseudotaxiphyllum elegans

Probably, Elegant Silk-Moss, Pseudotaxiphyllum elegans

Possibly Ring Pellia, Pellia neesiana

Black Spleenwort, Asplenium adiantum-nigrum

Mossy outcrop

Probably White Earwort, Diplophyllum albicans

Possibly Lesser Pocket-Moss, Fissidens bryoides

Artist's Bracket, Ganoderma applanatum

Probably Fluffy Dust Lichen, Lepraria finkii. Lepraria lichen are common on sandstone outcrops, and sometimes grow over mosses

Common Earthball, Scleroderma citrinum

Fairy Inkcap, Coprinellus disseminatus

Honeycomb weathering on the sandstone

Honeycomb weathering produces extensive networks of small cavities that form on rock surfaces. These patterns initially develop as many shallow depressions, but continued development produces deep chambers that are separated by thin septa of unweathered rock (Figure H9). Individual cavities are typically several centimeters in width and depth, the shape often being controlled by bedding planes, foliation, or other structural features of the rock in which they occur. In many localities the holes occur in association with a hardened surface layer formed when dissolution of ferruginous minerals has been followed by precipitation of ferric hydroxides near the outcrop surface. The thickness of this hardened layer may range from a few millimeters to several centimeters. Honeycomb Weathering | SpringerLink

Pincushion Moss, Leucobryum glaucum

Scaly Male Fern, ComplexDryopteris affinis

Probably Bifid Crestwort, Lophocolea bidentata

Male Fern, Dryopteris filix-mas



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