Fine-leaved water-dropwort

27th September 2009, Sunday

One of the more characteristic plants of the grazing marsh ditches at East Guldeford is fine-leaved water-dropwort Oenanthe aquatica, a species that in early spring has divided leaves that look very much like an aquatic plant, but as the summer progresses it emerges above water level with a characteristic swollen stem that has fine ridges running down it, with cross joints where the leaf stems emerge. The flowers are packed into white umbels.


Right now flowering is mostly over and plants are setting seed, but the characteristic stems allow this species to be recognised, even as dead stems – see below (50p piece for scale).

It is frequently found in shallow water and water bodies that dry out, and has an interesting distribution in the UK, down the east of England, with a series of records also from the Somerset Levels along the Welsh border to Lancashire. The New Atlas of the British Flora reported a moderate decline for this species, particularly in Eastern England, although Romney Marsh and the Somerset Levels appeared to retain a widespread population.