Resurrection of a Norfolk pond gem: Grass-poly Lythrum hyssopifolia
Resurrection of a Norfolk pond gem: Grasspoly Lythrum hyssopifolia CARL SAYER & JO PARMENTER The neat five-petalled flowers of Lythrum hyssopifolia (Grasspoly) that are borne singly in the plant’s leaf axils. Rob Peacock
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n a wet winter’s day in February 2020, an aged and contorted willow is heaved from the muddy ground, exposing long-buried layers of earth once punctured by cloven hooves and churned by horse and tumbler. As the Norfolk Ponds Project team finishes one of its final farmland pond restorations of the season in the village of Heydon, the digger leaves behind a newly opened-up and gently-shelving pond at the side of an arable field near a ‘retired’ farmyard.
The Norfolk Ponds Project
The Norfolk Ponds Project (NPP) aims to restore and conserve ponds in the county of Norfolk for the benefit of aquatic and terrestrial wildlife (Sayer & Greaves, 2020). Since 2015, the NPP has undertaken restoration work, involving major scrub and sediment removal, at some 15 highly terrestrialised farmland ponds in and around the village of Heydon, East Norfolk (v.c. 27). Following these restorations, the ponds have rapidly filled with wetland vegetation and a number of locally and/or nationally rare wetland plants have been recorded, including the Schedule 8 Najas marina (Holly-leaved Naiad) (1 pond), Hottonia palustris (Water-violet) (2 ponds), Typha angustifolia (Lesser Bulrush) (1 pond), Oenanthe
aquatica (Fine-leaved Water-dropwort) (7 ponds) and the uncommon charophytes Tolypella glomerata (Clustered Stonewort) (4 ponds) and Nitella opaca (Dark Stonewort) (1 pond) in particular. With the exception, of Najas marina, which likely arrived due to dispersal by wildfowl from a local shallow lake (Lansdown et al., 2016), all the other aforementioned species were undoubtedly derived from long-lived seedbanks disturbed during the restorations. In early July 2020, The NPP team were surveying along the high water mark of the recently restored pond as funded by the Natural England Great Crested Newt District Level Licensing Scheme. In amongst a new ‘meadow’ of Agrostis stolonifera (Creeping Bent), Rorippa palustris (Marsh Yellowcress) and Epilobium ciliatum (American Willowherb), they encountered a plant that was not immediately recognised, and so CS sent a photograph to JP. Six plants of Grass-poly Lythrum hyssopifolia L., the first confirmed record for the county in over a century, were thus discovered. L. hyssopifolia is a highly specialised annual flowering plant in the loosestrife family. It occurs at the northern limit of its European range in Britain (Webb, 1968) and is considered to be an archaeophyte, i.e. it arrived in the UK in ‘ancient’ BSBI NEWS 146 | January 2021
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