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Cookham – 3 August 2019

Renée Grayer led a walk to Winter Hill and Cock Marsh, starting from the National Trust car park at Cookham, on the morning of Saturday 4 August. The walk started out along a footpath which ran alongside a colourful ditch, where there were tall spikes of Purple Loosestrife, Hemp Agrimony, Great Willowherb, Yellow Loosestrife, Common Fleabane, Gypsywort and Common Valerian. The flower-heads of Wild Angelica, Hogweed and Hemlock Water-dropwort attracted many small insects. Other plants seen here included Square-stalked St John’s-wort, Water Figwort, Orange Balsam, Bulrush and False Fox Sedge. There were a few Banded Demoiselles and the round exit holes of the Hornet Clearwing Moth were noted at the base of a path-side Poplar. The track then led under a railway bridge which had an interesting collection of plants growing out of the old brickwork, including Pale Toadflax, Meadow Crane’s-bill, Wild Marjoram, Wall Rue and Hart’s-tongue Fern. The walk continued along a line of Hornbeam trees, through a kissing gate and out onto the National Trust’s grassland of Winter Hill and Cock Marsh. To the left of the path, the fine chalk grassland of Winter Hill sloped steeply upwards, with flowers including Musk and Dwarf Thistle, Harebell, Small Scabious, Common Bird’s-foot-trefoil, Wild Thyme, Lady’s Bedstraw, Salad Burnet, Clustered Bellflower, Squinancywort, Common Rock-rose, Fairy Flax, Eyebright and Quaking Grass. To the right of the path was Cock Marsh, with meadows beyond stretching for half a mile to the banks of the River Thames. Usually, there are a string of ponds in Cock Marsh, but following prolonged dry weather, these were reduced to damp patches – which made it easier to get close to the special wetland plants. These included Tubular Water-dropwort, Trifid Bur-marigold, Pink Water-speedwell, Marsh Speedwell, Brooklime, Marsh Yellow-cress, Water Forget-me-not, Creeping Jenny, Spear-leaved Orache, Common Water-crowfoot, Water-plantain and Water Dock. Many of the Pink Water-speedwell flower heads had the round galls of the Speedwell Weevil Gymnetron villosulum on the seed capsules. The feathery rosettes of Water-violet were found on an expanse of bare mud. Rarest find of the day was Brown Galingale, a small, tufted, annual sedge which was growing in the cattle-poached mud of the furthest pond. Purple-flowered Water Mint was abundant in the damper areas and visiting butterflies included Gatekeeper, Meadow Brown, Small and Green-veined White and Small Copper. Beneath an isolated Oak just above the edge of the marsh was a long line of red-capped fungi. They had yellow pores on the underside which stained dark blue when rubbed and were tentatively identified as Ruby Bolete Boletus rubellus.

Pictures by Rob Stallard

English NameScientific Name
Species seen along the ditch:
Yellow LoosestrifeLysimachia vulgaris
BittersweetSolanum dulcamara
Purple-loosestrifeLythrum salicaria
Bristly OxtonguePicris echioides
HogweedHeracleum sphondylium
Prickly Sow-thistleSonchus asper
Great WillowherbEpilobium hirsutum
WeldReseda luteola
False Fox-sedgeCarex otrubae
Common ValerianValeriana officinalis
Lords-and-LadiesArum maculatum
Creeping ThistleCirsium arvense
HemlockConium maculatum
Greater PlantainPlantago major
PineappleweedMatricaria discoidea
Wild AngelicaAngelica sylvestris
GypsywortLycopus europaeus
KnotgrassPolygonum aviculare
MeadowsweetFilipendula ulmaria
Pendulous SedgeCarex pendula
HopHumulus lupulus
Hemp-agrimonyEupatorium cannabinum
Hemlock Water-dropwortOenanthe crocata
TeaselDipsacus fullonum
Broad-leaved DockRumex obtusifolius
Fool’s Water-cressApium nodiflorum
Water FigwortScrophularia auriculata
Common FleabanePulicaria dysenterica
Water MintMentha aquatica
BulrushTypha latifolia
Square-stalked St John’s-wortHypericum tetrapterum
Lesser Water-parsnipBerula erecta
Orange BalsamImpatiens capensis
Clustered DockRumex conglomeratus
Wild CarrotDaucus carota
YarrowAchillea millefolium
Cock’s-footDactylis glomerata
MugwortArtemisia vulgaris
Water-plantainAlisma plantago-aquatica
AgrimonyAgrimonia eupatoria
Spear ThistleCirsium vulgare
Smooth Hawk’s-beardCrepis capillaris
Common RagwortSenecio jacobaea
Field BindweedConvolvulus arvensis
Hedge BindweedCalystegia sepium
Upright Hedge-parsleyTorilis japonica
Species on or near Railway Bridge:
Hart’s-tongueAsplenium scolopendrium
Wall-rueAsplenium ruta-muraria
Pale ToadflaxLinaria repens
Common ComfreySymphytum officinale
Wild MarjoramOriganum vulgare
Meadow Crane’s-billGeranium pratense
Traveller’s-joyClematis vitalba
White CampionSilene latifolia
Hedge MustardSisymbrium officinale
HornbeamCarpinus betulus
Species found on chalk hill:
Musk ThistleCarduus nutans
Small ScabiousScabiosa columbaria
Fairy FlaxLinum catharticum
SquinancywortAsperula cynanchica
Common Bird’s-foot-trefoilLotus corniculatus
Dwarf ThistleCirsium acaule
Quaking-grassBriza media
Wild ThymeThymus polytrichus
EyebrightEuphrasia agg.
Clustered BellflowerCampanula glomerata
Salad BurnetSanguisorba minor
Rough HawkbitLeontodon hispidus
Lesser HawkbitLeontodon saxatilis
Lady’s BedstrawGalium verum
HarebellCampanula rotundifolia
Common Rock-roseHelianthemum nummularium
Mouse-ear HawkweedPilosella officinarum
Thyme-leaved SandwortArenaria serpyllifolia
Species found along the ponds:
Trifid Bur-marigoldBidens tripartita
RedshankPersicaria maculosa
Spear-leaved OracheAtriplex prostrata
Lesser SpearwortRanunculus flammula
Pink Water-speedwellVeronica catenata
SilverweedPotentilla anserina
BrooklimeVeronica beccabunga
Marsh Yellow-cressRorippa palustris
Strawberry CloverTrifolium fragiferum
Welted ThistleCarduus crispus
Common MilkwortPolygala vulgaris
Water Forget-me-notMyosotis scorpioides
Remote SedgeCarex remota
Creeping JennyLysimachia nummularia
Tubular Water-dropwortOenanthe fistulosa
Marsh SpeedwellVeronica scutellata
Common Water-crowfootRanunculus aquatilis
Water-violetHottonia palustris
Common SorrelRumex acetosa
Brown GalingaleCyperus fuscus
Water DockRumex hydrolapathum
Small White
Green-veined White
Small Copper
Common Blue
Red Admiral
Meadow Brown

List by Renée Grayer