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  • Writer's pictureSim Elliott

Rocks, Trees, Fungi, Lichen, Bryophytes & Slime Molds. Eridge Rocks NR & Broadwater Warren. 19.11.22

Updated: Nov 22, 2022

I visited Eridge Rocks Nature Reserve (Sussex Wildlife Trust), because I knew it was a site of special scientific interest for lichen and bryophytes; next to it is RSPB Broadwater Warren, a mixed broad-leafed woodland with heathland, and mire forest; which is a particularly unusual habitat.

More details about Eridge Rocks and Broadwater Warren can be found at: Eridge Rocks | Sussex Wildlife Trust and Broadwater Warren Nature Reserve, Kent - The RSPB Eridge Rocks is on the border of East Sussex and Kent, just in East Sussex; Broadwater Warren is just in Kent.

To get to Eridge Rocks from Brighton by public transport is easy; just hope on a 29 bus to Tunbridge Wells and get off at Eridge Gree. At Eridge Green it is very short walk to the entrance of the reserve along Warren Farm Lane. However, there is only one bus an hour to Tunbridge Wells from Brighton, the other in-between 29s do not go as far, so make sure you get in the right bus. The timetabled time of the journey is 90 minutes, but when I visited the journey took 2 hours, both there and back: see: 29 - Brighton-Tunbridge Wells | Brighton & Hove Buses. Grid reference foe Eridge Rocks: TQ554357

I am quite new to fungi, lichen and bryophyte identification, so some of these identifications may be wrong. Feel free to let me know if I have got an identification wrong!

I used these resources for identification:

Stefan Buczacki, Chris Shields, Denys W Ovenden (2013) Collins Fungi Guide

Frank S Dobson (2018) Lichens: An illustrated guide to the British and Irish species

Ian Atherton, Sam Bosanquet, Mark Lawley (2019) Mosses and Liverworts of Britian and Ireland; a field guide

I have also used the Obsidentify App Mission -

and these websites:

Eridge Rocks

All sections of the text in italics are quotations, sources cited.

The photographs are in chronological order

From the Sussex Wildlife Trust's Reserve Profile Reserve profile | Sussex Wildlife Trust

These rocks are a distinctive feature of the High Weald, important in their own right as geological features, but also home to a suite of lower plants, including many rare mosses, liverworts and lichens. Surrounding the rocks is semi-natural ancient woodland, a mixture of Sweet Chestnut, Birch and Hazel with a good number of veteran Oak and Beech scattered throughout.

These sandstone rocks were probably formed in the last glacial period of the Ice Age 20 to 50,000 years ago, though the actual sand would have been deposited in a river system during the Cretaceous Period approximately 138 million years ago. They are characterised by large boulders and vertical joints which are widened through ongoing weathering and movement, some of which are now just about wide enough to squeeze through. The rocks themselves have developed a hardened crust which helps protect them from the weather and shows some characteristic types of weathering including strange small hollows known as honeycomb weathering and polygonal cracking on the rounded tops of the rocks.

The base of the rocks is often undercut to form overhangs and rock shelters. Archaeological investigations of some of these rock shelters at Eridge produced many struck flints of Mesolithic date and even some late Iron Age/early Romano-British smelting. As these flints were small and not of local origin it is thought that raw flints were transported into the area and then made into tools and weapons, suggesting the rock shelters were used temporarily by a small group of mobile hunter gatherers as has been found in similar locations in the Weald.

The lichen Bunodophoron melanocarpum a species thought to have been lost to shade at Eridge, had survived and is now expanding. The liverwort Harpanthus scutatus which had not been seen at Eridge since 1952 was recorded from a single quadrat in 2004 and continues to spread. Some of the other specialities at Eridge Rocks include the lichen Cladonia caespiticia a rare species on rocks and is very rare in Sussex but present in at least three locations at Eridge; the mosses Dicranum scottianum and Orthodontium gracile, and the leafy liverwort Bazzania trilobata. Reserve profile | Sussex Wildlife Trust

Here is the text from the web page on geodiversity at Eridge Rocks from the Sussex Wildlife Trust - it is a fascinating!

Geodiversity at Eridge Rocks

By Peter Anderton of the Sussex Biodiversity Partnership

Geodiversity is the variety of rocks, fossils, minerals, soils and landscapes which can be found and observed in any chosen area. It also includes the variety of natural processes, such as stream erosion, which modify our present day environment and which modified environments in the geological past. Geodiversity provides the foundation for habitats, ecosystems and biodiversity.

In Sussex, geodiversity is dominated by the Chalk rock which underlies the South Downs and by the older sandstones and clays which underlie the High Weald, the Low Weald and the Wealden Greensand landscapes. These older rocks were deposited during the Lower Cretaceous epoch of geological time from 145 to 100 million years ago. The sandstones at Eridge Rocks are characteristic of the middle part of the Wealden Group and were deposited about 135 to 133 million years ago.

A bedrock geological cross section between Eridge Rocks and Harrison’s Rocks. A geological cross section showing the underground layers of rock along a profile running from Eridge Rocks to Harrison’s Rocks. The Ardingly Sandstone at Eridge Rocks and Harrison’s Rocks forms the distinctive sandrock cliffs so typical of the High Weald. Underlying it are the thinner sandstones of the Lower Tunbridge Wells Sand unit and overlying it are the Grinstead Clay and lower part of the Upper Tunbridge Wells Sand.

A geological cross section showing the underground layers of rock along a profile running from Eridge Rocks to Harrison’s Rocks. The Ardingly Sandstone at Eridge Rocks and Harrison’s Rocks forms the distinctive sandrock cliffs so typical of the High Weald. Underlying it are the thinner sandstones of the Lower Tunbridge Wells Sand unit and overlying it are the Grinstead Clay and lower part of the Upper Tunbridge Wells Sand.

These impressive cliffs of Ardingly Sandstone are 10m high and form large blocks separated by vertical gaps. The massive sandstone blocks are made up of successive layers (beds) and the weaker layers have been picked out by weathering, forming notches.

Vertical gaps ... between the massive sandstone blocks are known as gulls. These follow naturally formed vertical fractures (called joints) which have been opened up partly by weathering and erosion but often by movement of the blocks themselves. This movement probably occurred during cold climate (ice age) episodes in the Pleistocene period of geological time, the last of which ended 10,000 years ago. Melting of frozen ground would have allowed blocks to move downslope.

The Ardingly Sandstone is quite soft and friable but the cliff faces are covered with a dark grey weathered crust which helps to protect the underlying sandstone from erosion. When exposed the fresh sandstone is lighter coloured.

[Some of the] ... sandstone block[s] ... [are]about 8 m high with an undercut base and large overhang. The undercutting may be due to greater erosion of a weaker layer at the base of the cliff or the sapping action of water seeping from the base of the sandstone where it meets the underlying less permeable rock. The result is to undermine the cliff face.

Bedding layers are relatively horizontal and weathering has picked out weaker layers forming notches.

[Some of the sandstone faces] ... show bedding layers pockmarked by honeycomb weathering. This forms by salt weathering when saline water percolating through the sandstone evaporates near the surface and forms salt crystals which can grow and break the rock to form small pits. As it does not penetrate the weathering crust the honeycomb weathering here is probably a relic of former climatic conditions during the Pleistocene period.

[Some of the sandstone faces are] .... 10m high .... [and have] rounded upper surfaces covered with polygonal cracks. These may have formed under cold climate conditions due to alternate freezing and thawing. Alternatively they may result from cracking of a thin mineralised crust. The face[s] [show] ... honeycomb weathering pits.

Rocks provide a valuable window into past environments and biodiversity. [Some sandstone blocks] ... expose a set of trough like or dipping bedding patterns, which show that it was deposited a braided stream environment. The Wealden rocks were deposited in nonmarine environments and this interpretation is supported by the fossil evidence. Characteristic fossils range from freshwater gastropods and fish to reptiles and dinosaurs. Geodiversity at Eridge Rocks | Sussex Wildlife Trust

These rocks are designated a Site of Special Scientific Interest due to the community of plants growing on them. Eridge Rocks | Sussex Wildlife Trust

Dramatic sandstone outcrops are clung to by an eclectic mix of conifers, deciduous trees, bamboo, mosses, liverworts and ferns. Venture further into the woodland through coppiced chestnuts, looking out for some veteran oaks and yew. Eridge Rocks - Woodland Trust

Eridge Green church, Warren Farm Lane, which leads to Eridge Rocks is immediately to the left (south) io the church.

The footpath sign on Warren Farm Lane

Eridge Rocks Nature Reserve

Sussex Wildlife Trust reserve information boards

Stubby-stalked clad lichen, Cladonia caespitica; the first lichen I saw; and the one mentioned by the Sussex Wildlife Trust: Some of the other specialities at Eridge Rocks include the lichen Cladonia caespiticia a rare species on rocks and is very rare in Sussex but present in at least three locations at Eridge.

A dead decomposing tree, leaning against the rocks; the home to a range of fungi

Fukasawa, Y. (2021). Ecological impacts of fungal wood decay types: A review of current knowledge and future research directions. Ecological Research, 36( 6), 910– 931.

Forest ecosystems represent a large component of the global carbon stock as they are estimated to stock 861, and assimilate ~2.4, petagrams of carbon (Pg C) annually (Pan et al., 2011). Carbon stock in forests is maintained dynamically as the balance between carbon assimilation by living plants and the decomposition of dead plant materials, and thus is sensitive to local natural disturbances such as windstorms, wildfires, and pest or pathogen outbreaks, all of which are closely associated with global climate change (Kurz et al., 2008; Pan et al., 2011). Deadwood may contribute only ~8% (73 Pg C) of forest carbon stock on average (Pan et al., 2011), or less according to the latest measure of the carbon fraction of deadwood (Martin et al., 2021). However, this increases considerably in cases of deforestation due to disturbance; indeed, carbon loss due to wood decomposition has the potential to transform a forest from a sink to source of carbon (Kurz et al., 2008). Understanding the deadwood decomposition process is therefore essential for predicting global carbon cycling under climate change.

Given its slow decomposition rate, deadwood is an important habitat as well as a carbon source for a variety of organisms in forest ecosystems (Bunnell & Houde, 2010; Stokland et al., 2012). Saproxylic communities [communities of organisms that are dependent on dead or decaying wood] consist not only of saprotrophic decomposers such as fungi, bacteria, protozoans, and invertebrates, but also autotrophic [organism that can produce its own food using light, water, carbon dioxide, or other chemicals] algae (including lichens), bryophytes, and vascular plants (Harmon et al., 1986; Stokland et al., 2012). The importance of deadwood as a site of regeneration of forest trees has been reported in boreal [climatic zone south of the Arctic, especially the cold temperate region dominated by taiga and forests of birch, poplar, and conifers] and subalpine (Harmon & Franklin, 1989; Hofgaard, 1993; Orman et al., 2016), temperate (Fukasawa, Komagata, & Kawakami, 2017; Harmon et al., 1986; Ota et al., 2012), and tropical forests (Sanchez et al., 2009; Santiago, 2000; Van der Meer et al., 1998). Focusing on ecological community networks associated with tree regeneration on deadwood is important for understanding forest dynamics which is another critical aspect of predicting the global carbon cycle.

Among saproxylic communities, fungi are the most important group of organisms for wood decomposition in forest ecosystems due to their capability to produce extracellular enzymes and actively transfer carbon, nutrients, water, and oxygen along highly branching hyphal networks (Boddy, 1991; Cragg et al., 2015; Swift et al., 1979). Thousands of fungal species have been reported to be living on deadwood (Stokland et al., 2012), including Basidiomycota, Ascomycota, and Mucoromycota. In particular, species of Basidiomycota and Ascomycota play a major role in the decomposition of lignocellulose, a structural component of wood that consists of lignin, cellulose, and hemicellulose and constitutes more than 90% of total wood mass (Eaton & Hale, 1993; Eriksson et al., 1990; Vogt et al., 1986). Enzymatic degradation of lignocellulose by fungi and species-specific fungal preferences for different lignocellulose components lead to considerable changes in the physicochemical properties of decaying wood, which is the basis for the categorization of fungal decay into “decay types” (white-, brown-, and soft-rot; Eaton & Hale, 1993). It is essential to consider the biological traits of fungal decomposer communities to understand the decay rate of organic matter (Lustenhouwer et al., 2020; Maynard et al., 2019), vegetation development (Steidinger et al., 2019) and, consequently, carbon sequestration in terrestrial ecosystems (Averill et al., 2014; Crowther et al., 2019). Ecological impacts of fungal wood decay types: A review of current knowledge and future research directions - Fukasawa - 2021 - Ecological Research - Wiley Online Library

Common Jellyspot, Dacrymyces stillatus

A saprotrophic species that occurs on dead wood.

Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophicextracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi (for example Mucor) and soil bacteria. Saprotrophic microscopic fungi are sometimes called saprobes; saprotrophic plants or bacterial flora are called saprophytes (sapro- 'rotten material' + -phyte 'plant'), although it is now believed that all plants previously thought to be saprotrophic are in fact parasites of microscopic fungi or other plants. The process is most often facilitated through the active transport of such materials through endocytosis within the internal mycelium and its constituent hyphae. Saprotrophic nutrition - Wikipedia

Probably Variable Oysterling, Crepidotus variabilis, another saprotrophic species

Turkeytail, Trametes versicolor. Formerly known in the UK as the Many-Zoned Polypore. A common polypore (bracket) fungus found throughout the world, and another saprotrophic species. Turkeytail is used in Chinese medicine, however, and there are also scientific reports of its use in anti-cancer drug development. Trametes versicolor, Turkeytail fungus (

The logs in which the Turkeytake was grwing

Stereun hisruitam, Hairy Curtain Crust growing on a dead log.

Bark separating form the log; probably there are a range if fungi and slime molds between the log and the bark

Possibly, Branched pixie-cup lichen, Cladonia ramulosa. Definitiely a Cladonia sp.

An ancient yew growing on the rocks

same rocks - wider view.

Dotted Bush Lichen, Ramalina farinacea

... an epiphytic bushy shaped (fruticose) lichen common to areas with Mediterranean, subtropical, or temperate climates. It is in the genus Ramalina of the family Ramalinaceae. The coexistence of two different species of the Trebouxia genus of green algae at the same time were found to be in each specimen collected in widely distributed populations. The algae thrive in different temperature and light environments. It is thought this demonstrates an ability of the lichen with two simultaneous green algae partners to proliferate in a wider range of habitats and geographic areas. This lichen species is characterized by its long, narrow branches (less than 2 to 3 millimeters wide) and clearly defined marginal soralia. It is most often found at low elevations on trees and shrubs.

A dead tree in the woods that surround the rocks

On a branch of this tree, seemingly cut by a tree surgeon, there was a "wood" of lichen growing; too far off to identify, but probably a Clodonia sp

Another dead tree

Another Cladonia sp lichen, possibly Cladonia coniocrea or Cladonia caespiticia

Probably Rusty Swan-Neck Moss, Campylopus flexosus

Probably the lichen, Hypotrachyna afrorevoluta or Hypotrachyna revoluta A very beautiful lichen.

Dead tree

Trees on the rocks

A Dryopteris, wood ferns, species

Oak Pin fungi Cudoniella acicularis with Cypress-leaved Plaitmoss, Hypnum cupressiforme, on dead oak

Possibly Black Spleenwort, Asplenium adiantum-nigrum, a common species of fern.

Extraordinary Rocks

Possibly, Skeletocutis amorpha is a species of poroid [polypore] fungus

Probably, The Blob, Physarum polycephalum, a slime mold. Seriously, the common name of Physarum polycephalum is The Blob. Its an acellular slime mold or myxomycete. Physarum polcephalum has been extensive studied with regard to how it makes decisions about what it chooses to eat. It makes decisions through distributed networks not a central brain.

Throughout evolution, living systems have developed mechanisms to make adaptive decisions in the face of complex and changing environmental conditions. Most organisms make such decisions despite lacking a neural architecture. This is the case of the acellular slime mold Physarum polycephalum that has demonstrated remarkable information processing and problem-solving abilities. Previous studies suggest that the membrane of P. polycephalum plays an important role in integrating and processing information leading to the selection of a resource to exploit. The cyclical contraction-relaxation pattern of the membrane changes with the local quality of the environment, and individual contractile regions within a P. polycephalum can entrain neighboring regions, providing a potential mechanism for information processing and propagation. In this study, we use an information-theoretic tool, transfer entropy, to study the flow of information in single tubule segments of P. polycephalum in a binary choice between two food sources. We test P. polycephalum tubules in two food choice conditions, where the two available options are either symmetric in their nutrient concentrations or with one more concentrated in nutrients than the other (i.e., asymmetric). We measure the contractile pattern of the P. polycephalum membrane and use these data to explore the direction and amount of information transfer along the tubule as a function of the cell's final decision. We find that the direction of information transfer is different in the two experimental conditions, and the amount of information transferred is inversely proportional to the distance between different contractile regions. Our results show that regions playing a leading role in information transfer changes with the decision-making challenges faced by P. polycephalum.

Boussard Aurèle, Fessel Adrian, Oettmeier Christina, Briard Léa, Döbereiner Hans-Günther

and Dussutour Audrey,2021, Adaptive behaviour and learning in slime moulds: the role of oscillations Phil. Trans. R. Soc. B3762019075720190757 Adaptive behaviour and learning in slime moulds: the role of oscillations | Philosophical Transactions of the Royal Society B: Biological Sciences (

To be identified

To be identified

To be identified

Glistening Inkcap, Coprinellus micaceus, a very cosmopolitan mushroom, growing in Slender-beaked Moss, Isothecium myosuroides; a very common bryophyte. Eridge Rocks Nature Reserve. Glistening Inkcaps are almost always found in combination with moss

An Orthotrichum species, possibly Wood Bristle-moss, Orthotrichum affine

Lichen (bottom): Black Stone Flower, Parmotrema perlatum

Tiny, tiny mushroom, possibly Inocybe species

"Forest" of Candlesnuff Fungi, aka Stagshorn, Xylaria hypoxylon, on Cypress-leaved Plaitmoss, Hypnum cupressiforme.

Possibly Scurfy Deceiver, Laccaria proxima

More Candlesnuff

Honeycomb weathering

Honeycombing mostly occurs on inclined surfaces facing the sun, a fact that was brought home to me when we recently visited Australia and noted the near complete absence of honeycombing facing south, the reverse of what happens here in the northern hemisphere (see Appendix 3). A fundamental step in understanding the geometry of honeycombing is to realize that it is not determined by the pattern of surface wetting, rather it is dictated by movement of water from within the rock to the surface. Random wave and wind-borne splashes could not possibly create the well-ordered patterns that are commonly observed. Honeycombing occurs only on porous rocks—you seldom see it on shale—but some normally impermeable rocks are sometimes honeycombed because they have become porous as the result of chemical weathering, or because they are volcanic and contain microvesicles. Doe, N.A., The geometry of honeycomb weathering of sandstone, SHALE 26, pp.31–60, November 2011 Geometry of honeycomb weathering in sandstone (

Cypress-leaved plaitmoss, Hypnum cupressiforme

Chestnut seed cases on a branch

Lichen (bottom) Cladonia species, possibly Cladonia coniocraea

Common Powderhorn/Powderhorn Cup Lichen, Cladonia coniocraea, and Silky Forklet-moss, Dicranella heteromalla

Bank Haircap Moss, Polytrichum formosum

Common Powderhorn/Powderhorn Cup Lichen, Cladonia coniocraea

To be identified

Oak Pin, Cudoniella acicularis

Oakmoss Lichen, Evernia prunastri

Root Rot Fungus, Heterobasidion annosum

Whitewash lichen, Phlyctis argena

Branched Pixie-Cup Lichen, Cladonia ramulosa

To be identified

To be identified

RSPB Broadwater Warren Text from Broadwater Warren Nature Reserve, Kent - The RSPB


Heathland and woodland restoration is returning Broadwater to its historic habitat of centuries ago, a wildlife-rich mosaic of heathland and native woodland with scrubby woodland margins, scattered stands of pines and rare woodland mire. Threatened bird species like woodlark and nightjar have returned to the site, along with adders, bumblebees and butterflies, and new views across the landscape have been opened up. The pond is now a haven for dragonflies and frogs, visited by a kingfisher and heron. The woodlands are being managed for vulnerable species like marsh tit and dormouse.


The 10-year project to restore the area back to heathland started in 2007. The first step towards restoration of the heathland from conifer plantation involved removing dense young conifer trees and harvesting some of the mature pine and spruce. Until 2017, each winter, selected areas of conifer plantation were removed in a carefully planned schedule, to limit the impact on wildlife.

Bees, butterflies and other insects have come back in earnest and track edges are now blossoming with wildflowers like purple self-heal, common centaury and tormentil. Woodlark returned to the site in 2012 and bred for the first time in nine years. Since the project started our heathland birds - woodlark, tree pipit and nightjar have all increased in number. Dartford warblers have been seen over the last few winters and the hope is that it wont be long till they call Broadwater Warren home.

The restoration of the Decoy Pond was completed in 2014 and has transformed the area from a dark and gloomy damp spot to a hive of activity and beauty. The removal of oppressive conifers and coppicing of birch and alder around the edge has opened up the water to more light and warmth. The ponds across the reserve are now home to an amazing 22 different species of dragonfly and damselfy, including heathland specialists such as black darter.

By the end of the ten-year project in 2017, Broadwater is now roughly half heathland and half woodland. The woodland is a mix of native broadleaved trees, with areas of coppice and interspersed pines.

Open glades and sunny rides are now starting to create nectar rich corridors, full of flowers and butterflies. Areas of wet woodland and large oaks provide homes for lesser spotted woodpecker and marsh tit, while the dense scrubby understorey will host rare dormice and song thrushes. Broadwater Warren Nature Reserve, Kent - The RSPB

Vintage 300-year-old Oak

Hairy Curtain Crust, Stereum hirsutum

growing on bark and round branches and twigs of a dead Silver Birch, Betula pendula. 18.11.22. These are resupinate fungi, from the botanical term meaning ‘upside-down’ or ‘upward facing’, because it is from these patches, the exposed “hymenial surface” or “hymenophore” that face upward and outward from the fungi’s woody host, that they release their spores. ... Like our conventional mushrooms and toadstools, they spend most of the year out of sight and out of mind, existing as a network of mycelium spreading within their chosen substrate. When they do appear, they can be seen everywhere within the woodland landscape. Monthly Mushroom: Hairy Curtain Crust (Stereum hirsutum) (

Bitter Oysterling, Panellus stipticus

Purplepore Bracket, Trichaptum abietinum

Birch Mazegill, Lenzites betulinus. on Silver Birch. RSPB Broadwater Warren. 19.11.21. The green tinge is probably from algae growing on the Mazegill.

It is hard to separate Birch Mazegill from Turkeytail at first sight. "From the top this attractive bracket is easily misidentified. There are so many colour variations in Trametes versicolor [Turkeytail] that it is almost forgivable to assume that any fan-shaped thin bracket with concentric, many-zoned bands on its upper surface must be yet another Turkeytail. No so! Just as variable in colour as Trametes versicolor is this thin and leathery fan-like bracket, again with many concentric colour bands, but there is one very important feature distinguishing it from Turkeytail... it has gills.., Lenzites betulinus Birch Mazegill identification (

The term "algae" (singular: alga) is used to denote a vast array of plant-like organisms. Modern genetic studies have shown conclusively that the organisms called algae belong to several different kingdoms and are mostly not plants at all. We should probably abandon the term altogether, but it has a long history and is in fact not altogether useless.

The organisms we call algae are a diverse group of often very distantly related species. All of them lack roots and real leaves, although some of the larger ones have root-like structures called holdfasts and flat leaf-like blades. All contain chlorophyll and all are photosynthetic, but in many groups the green colour is masked by a variety of "accessory pigments". The smallest algae are one-celled and only a few micrometers in diameter. Mutualisms between fungi and algae (

To return home I had to walk back past Eridge Rocks

Resinous Polypore, Ischnoderma resinosum, growing inside a dead tree

More honeycombe weathering