Northern Ireland's Priority Species

Oenanthe fistulosa – tubular water-dropwort

 

Distribution map

Click here to view an interactive map of the Northern Ireland dataset as currently collated by CEDaR.
The map is generated through the NBN Gateway using their Interactive Mapping Tool.

 

Oenanthe fistulosa L.
Family: Apiaceae

This is a distinctive umbellifer with glabrous stems and just 2-5 rays on its umbels. In England the species has suffered a considerable decline due to drainage and reseeding. While some sites have been lost in Northern Ireland, Tubular Water-dropwort is still widespread in Fermanagh.

In brief

  • Around Lough Neagh Tubular Water-dropwort is widespread but sparingly distributed (Harron 1986) while the species has not been seen recently at many of its previous sites in the east of the province (Hackney 1992)
  • The species has, since 1975, been recorded on 107 monads in County Fermanagh, with almost 100 of these being in the Upper Lough Erne Basin
  • The species can be found in swampy ground, usually where the surrounding vegetation is at least 30cm high
  • It is possible to see the species from late May until late September with the main flowering time being July
  • Tubular Water-dropwort has declined in England and probably in the east of Northern Ireland

Species description
This umbellifer is a hollow-stemmed, little branched, glaucous, greyish-green plant of wet places which are flooded for at least part of the year. The upper leaves are once pinnate with distinctive inflated stalks. The flowers are white with 2-5 rays and usually no lower bracts.

Life cycle
Tubular Water-dropwort is a perennial with tuberous roots and both terrestrial and emergent plants flower and fruit freely. There is no vegetative means of reproduction (Preston and Croft 1997).

Similar species
In Ireland, the only similar species to Tubular Water-dropwort is Oenanthe lachenalii (Parsley Water-dropwort). Parsley Water-dropwort is a plant of brackish water and salt marshes, has a nearly solid stem, is a different shade of green. Its flower ahs 7-10 rays and has both bracts and bracteoles.

How to see this species
The species can be seen flowering in July and August in areas about low lying lakes where there is seasonal flooding. This habitat is frequent in the Upper Lough Erne Basin, especially in the area about Crom Estate.

Current status
The species is still widespread and fairly frequent about Upper Lough Erne (it has been recorded in 107 monads since 1975) but is much less frequent in the rest of Northern Ireland.

Why is this species a priority in Northern Ireland?
Tubular Water-dropwort has declined in England and probably in the east of Northern Ireland.

Threats/Causes of decline
The main threats to this species are drainage, reseeding of meadows and other agricultural improvements. A buffer zone of up to 20 meters should, if possible, be left about lakes when improvements are being undertaken so that species such as this are left with a suitable habitat.

Conservation of this species

Current action
Many of the sites where the species occurs, as about Upper Lough Erne, are ASSIs.

Proposed objectives/actions
Ensure that the current population is maintained, and if possible increased, through appropriate habitat management.

What you can do
If you think you have found this species, contact your local Biodiversity Officer.
Or you can submit your records to CEDaR
The study of wild plants is an interesting hobby for anyone interested in the outdoors. The Botanical Society of the British Isles welcomes beginners to its field trips. The BSBI can be contacted through www.bsbi.org.uk/

Further information

Links
Northern Ireland Vascular Plant Database

Literature
Hackney, P. (1992). Stewart and Corry’s Flora of the North-east of Ireland (third Edition). Institute of Irish Studies, Queen’s University, Belfast.
Harron, J. (1986). Flora of Lough Neagh. Irish Naturalists’ journal Committee and the University of Ulster, Coleraine.
McNeill, I. (2010). The Flora of County Tyrone. National Museums of Northern Ireland, Belfast.
Preston, C.D., Crift, J.M. (1997). Aquatic Plants in Britain and Ireland. Harley Books, Colchester.
Preston, C.D., Pearman, D.A. & Dines, T.D. (2002). New Atlas of the British and Irish Flora. Oxford University Press, Oxford.

Text written by:
Robert Northridge