Penn's Rocks

Site of Special Scientific Interest · 51.0946, 0.1757

Condition (Natural England)

Favourable (4)
UnitFeatureConditionArea (ha)Assessed
TQ516347 Favourable 4.48 2024-03-25
TQ517344 Favourable 4.48 2024-03-25
TQ520345 Favourable 4.48 2024-03-25
TQ524350 Favourable 5.94 2024-03-25

Geology & landscape

Rock Type: Sandstone

Description

Area, 10.1 ha. 25 ac. Description At Penn's Rocks outcrops of the Ardingly Sandstone Formation of the Hastings Beds are exposed in a steep sided wooded valley. The resulting 'sandrock' is a nationally rare habitat which supports a rich community of ferns and bryophytes mosses and liverworts including many 'Atlantic' species which are uncommon in south east England. The site comprises four blocks of woodland each with sandstone outcrops. In the southern areas pedunculate oak Quercus robur and beech Fagus sylvatica are dominant, with varying amounts of silver birch Betula pendula, yew Taxus baccata and holly Ilex aquifolium over a ground flora of bramble Rubus fruticosus and bracken Pteridium aquilinum. In the north Scot's pine Pinus sylvestris and silver birch dominate in a heathy woodland over a ground layer including heather Calluna vulgaris, bilberry Vaccinium myrtillus and bracken. The site also contains small areas of coppiced sweet chestnut Castanea sativa and improved grassland. The warm, moist microclimate provided by this woodland cover has allowed species to remain which are now restricted to northern and western Britain and a few localities in the Weald. This sandrock community contains many uncommon bryophytes including Orthodontium gracile, Bazzania trilobata, Saccogyna viticulosa and Harpanthus scutatus.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
bracken Pteridium aquilinum LC fern dennstaedtiaceae
bramble Rubus fruticosus LC herb rosaceae
greater whipwort Bazzania trilobata LC liverwort jungermanniales
stipula flapwort Harpanthus scutatus LC liverwort jungermanniales
straggling pouchwort Saccogyna viticulosa LC liverwort jungermanniales
billberry Vaccinium myrtillus LC shrub ericaceae
bell heather or ling Calluna vulgaris NT shrub dwarf ericaceae
birch Betula pendula LC tree betulaceae
sweet chestnut Castanea sativa LC tree fagaceae
beech Fagus sylvatica LC tree fabiaceae
holly Ilex aquifolium LC tree aquifoliaceae
Scot's pine Pinus sylvestris LC tree pinaceae
common oak Quercus robur LC tree fagaceae
yew Taxus baccata LC tree taxaceae

Plant communities

W25 — Bracken scrub

Pteridium aquilinum-Rubus fruticosus underscrub

Hedera helix, Acer pseudoplatanus, Fagus sylvatica, Quercus robur, Fraxinus excelsior, Sambucus nigra, Ulex europaeus, Crataegus monogyna, Prunus spinosa, Luzula multiflora, Mnium hornum, Brachythecium rutabulum, Kindbergia praelonga, Angelica sylvestris, Conopodium majus, Heracleum sphondylium, Arum maculatum, Cirsium arvense, Lonicera periclymenum, Silene dioica, Stellaria holostea, Mercurialis perennis, Geranium robertianum, Glechoma hederacea, Teucrium scorodonia, Hyacinthoides non-scripta, Chamerion angustifolium, Circaea lutetiana, Digitalis purpurea, Rumex acetosa, Anemone nemorosa, Ficaria verna, Potentilla erecta, Rosa arvensis, Rosa canina, Rubus fruticosus agg., Rubus idaeus, Galium aparine, Galium mollugo sens.lat., Galium saxatile, Urtica dioica, Viola riviniana, Agrostis capillaris, Anthoxanthum odoratum, Arrhenatherum elatius, Dactylis glomerata, Festuca rubra, Holcus lanatus, Holcus mollis, Poa trivialis, Pteridium aquilinum, Dryopteris dilatata, Dryopteris filix-mas