The MK Natural History Society group assembled at 7pm at Holy Trinity church, with its fine yews, cedar and black walnut trees and walked north towards the River Great Ouse, through the Ouse Valley Park, managed for cattle-grazing and hay-making by the Parks Trust.   As we walked downhill to the floodplain, we viewed the long-abandoned site of Old Wolverton village on the western side of the path, we crossed a dried-up ditch by the double-gated bridge.

From the bridge on our left, in the ditch just below the hedge, several of the group spotted a plant which no one was confident of its identification.  We used our Society members’ ideas on its potential “ID”, later checking a variety of guides to the British flora, and a variety of “Apps” were “zapped” to seek its possible ID though all of us are cautious about the generally American databases most Apps use.

On a visit about 10 days later Joe Clinch and I confirmed it to be Fools Watercress Apium nodiflorum. It is a member of the carrot family, Apiaceae, and in that damp habitat it might have been Lesser Water Parsnip or a poisonous dropwort, both of which are seriously poisonous.

In the next field we entered a fine area of meadow on the floodplain, now managed by the Parks Trust. (This is River Field East SP 80020 41474.)   A well-worn field path took us through the fine grasses and flowers of mid-July.

I am grateful to Charles Kessler for the grasses list and for his input on their identification, which seemed more possible in high summer when their “flowery heads” seemed to differentiate one from another.

At the bank of the Ouse we walked east towards the Iron Trunk aqueduct, an important historic spot where the Grand Union Canal crosses the river.   When we were right on the riverside below the Iron Trunk, we noted native water lily in the slow-flowing water, as well as Purple loosestrife and Agrimony, alongside “eggs and bacon”, Birds-foot trefoil, a member of the pea family, and Creeping cinquefoil, a member of the rose family.

Some members explored the dry canal embankment just by the brick-built pumping station adjacent or read the Canal and River Trust’s informative signage for the history of the construction of the Iron Trunk, after earlier attempts failed.   We walked through the foot tunnel for people and horses, and continued the walk along the east side of the canal, along the towpath, in a southerly direction towards the Galleon pub.

The canal bank and hedgerow/scrubby woodland on our left side rewarded us with a wealth of flowers, sedges and grasses before we concluded at sunset on the canal road bridge.  See attached Plant List.

Plants of note were checked out by Joe Clinch and myself, with Linda Murphy confirming that Black horehound was seen in the hedgerow.  This was a new find for me; if seen before I’d have thought it would be Marsh woundwort!  I found it really helpful to have many observers contributing information from childhood haunts and other locations in Britain.

Thank you to everyone who participated, and made leading the walk a very enjoyable experience, with the challenge remaining for next year – to find the elusive Fairy flax.

A plant list is attached demonstrating the enthusiasm with which my colleagues, Joe Clinch and Charles Kessler, tackled the major task of identifying such a wealth of botanical diversity. The list contains 69 plants, including 10 grasses.

Plant list – Fairy Flax walk Old Wolverton 12.07.22

Jenny Mercer
August 2022