The Field Elm cultivar Ulmus minor 'Plotii', commonly known as Lock Elm or Lock's Elm (its vernacular names), Plot's Elm or Plot Elm, is endemic mainly to the East Midlands of England, notably around the River Witham in Lincolnshire and in the Trent Valley around Newark on Trent, in the village of Laxton, Northamptonshire. Two further populations existed in Gloucestershire. It has been described as Britain's rarest native elm, and recorded by The Wildlife Trust as a nationally scarce species.