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.

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Pictures by Rob Stallard

English Name	Scientific Name
Species seen along the ditch:
Yellow Loosestrife	Lysimachia vulgaris
Bittersweet	Solanum dulcamara
Purple-loosestrife	Lythrum salicaria
Bristly Oxtongue	Picris echioides
Hogweed	Heracleum sphondylium
Prickly Sow-thistle	Sonchus asper
Great Willowherb	Epilobium hirsutum
Weld	Reseda luteola
False Fox-sedge	Carex otrubae
Common Valerian	Valeriana officinalis
Lords-and-Ladies	Arum maculatum
Creeping Thistle	Cirsium arvense
Hemlock	Conium maculatum
Greater Plantain	Plantago major
Pineappleweed	Matricaria discoidea
Wild Angelica	Angelica sylvestris
Gypsywort	Lycopus europaeus
Knotgrass	Polygonum aviculare
Meadowsweet	Filipendula ulmaria
Pendulous Sedge	Carex pendula
Hop	Humulus lupulus
Hemp-agrimony	Eupatorium cannabinum
Hemlock Water-dropwort	Oenanthe crocata
Teasel	Dipsacus fullonum
Broad-leaved Dock	Rumex obtusifolius
Fool’s Water-cress	Apium nodiflorum
Water Figwort	Scrophularia auriculata
Common Fleabane	Pulicaria dysenterica
Water Mint	Mentha aquatica
Bulrush	Typha latifolia
Square-stalked St John’s-wort	Hypericum tetrapterum
Lesser Water-parsnip	Berula erecta
Orange Balsam	Impatiens capensis
Clustered Dock	Rumex conglomeratus
Wild Carrot	Daucus carota
Yarrow	Achillea millefolium
Cock’s-foot	Dactylis glomerata
Mugwort	Artemisia vulgaris
Water-plantain	Alisma plantago-aquatica
Agrimony	Agrimonia eupatoria
Spear Thistle	Cirsium vulgare
Smooth Hawk’s-beard	Crepis capillaris
Common Ragwort	Senecio jacobaea
Field Bindweed	Convolvulus arvensis
Hedge Bindweed	Calystegia sepium
Upright Hedge-parsley	Torilis japonica
Species on or near Railway Bridge:
Hart’s-tongue	Asplenium scolopendrium
Wall-rue	Asplenium ruta-muraria
Pale Toadflax	Linaria repens
Common Comfrey	Symphytum officinale
Wild Marjoram	Origanum vulgare
Meadow Crane’s-bill	Geranium pratense
Traveller’s-joy	Clematis vitalba
White Campion	Silene latifolia
Hedge Mustard	Sisymbrium officinale
Hornbeam	Carpinus betulus
Species found on chalk hill:
Musk Thistle	Carduus nutans
Small Scabious	Scabiosa columbaria
Fairy Flax	Linum catharticum
Squinancywort	Asperula cynanchica
Common Bird’s-foot-trefoil	Lotus corniculatus
Dwarf Thistle	Cirsium acaule
Quaking-grass	Briza media
Wild Thyme	Thymus polytrichus
Eyebright	Euphrasia agg.
Clustered Bellflower	Campanula glomerata
Salad Burnet	Sanguisorba minor
Rough Hawkbit	Leontodon hispidus
Lesser Hawkbit	Leontodon saxatilis
Lady’s Bedstraw	Galium verum
Harebell	Campanula rotundifolia
Common Rock-rose	Helianthemum nummularium
Mouse-ear Hawkweed	Pilosella officinarum
Thyme-leaved Sandwort	Arenaria serpyllifolia
Species found along the ponds:
Trifid Bur-marigold	Bidens tripartita
Redshank	Persicaria maculosa
Spear-leaved Orache	Atriplex prostrata
Lesser Spearwort	Ranunculus flammula
Pink Water-speedwell	Veronica catenata
Silverweed	Potentilla anserina
Brooklime	Veronica beccabunga
Marsh Yellow-cress	Rorippa palustris
Strawberry Clover	Trifolium fragiferum
Welted Thistle	Carduus crispus
Common Milkwort	Polygala vulgaris
Water Forget-me-not	Myosotis scorpioides
Remote Sedge	Carex remota
Creeping Jenny	Lysimachia nummularia
Tubular Water-dropwort	Oenanthe fistulosa
Marsh Speedwell	Veronica scutellata
Common Water-crowfoot	Ranunculus aquatilis
Water-violet	Hottonia palustris
Common Sorrel	Rumex acetosa
Brown Galingale	Cyperus fuscus
Water Dock	Rumex hydrolapathum
Butterflies:
Small White
Green-veined White
Small Copper
Common Blue
Red Admiral
Gatekeeper
Meadow Brown

List by Renée Grayer