Northern Ireland's Priority Species

Spiranthes romanzoffiana – Irish lady's-tresses


Distribution map

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Spiranthes romanzoffiana Cham.
Family: Orchidaceae

This attractive wild orchid is distributed right across North America. It was first described scientifically from plants found on the island of Unalaska by Adelbert von Chamisso, the botanist on a Russian expedition which visited the Aleutian Islands of Alaska in 1816. In Europe, it is confined to Ireland and western Great Britain. The fact that the British and Irish populations are widely separated from the American by the Atlantic Ocean raises interesting questions about their origin. Some botanists believe this plant to have arrived only recently from North America, perhaps carried as seed on the feet of migrating birds.

In brief

  • The genus Spiranthes is one of the most cosmopolitan of orchid genera with approximately 300 species in all continents except Africa.

  • This species was first found in Ireland and Europe in 1810 in County Cork, but subsequently found in many other parts of the island and many places in west Scotland.

  • Northern Ireland and Scotland together hold the largest population of this orchid within Europe.

  • For many years up to the 1960s, the main area of occurrence of this plant in Northern Ireland was about the shores of Lough Neagh and Lough Beg.

  • It usually grows in wet marshy ground which is not too acidic, and at low altitudes.

  • It is best searched for in late July and August, when it is in flower.

  • In the past, sites have been damaged or destroyed by drainage, burying under dredged waste or agricultural improvement.

  • North American English-language names include Romanzof’s lady’s-tresses and hooded lady’s-tresses.

    Species description
    The plant grows to about 30cm tall, but often much shorter, with long, narrow leaves arranged up the stems. The flowers are tubular, whitish or cream-coloured, scented, and arranged in three slightly twisted rows along the spike.

    Life cycle
    The flowering period is from the end of July to the end of August. The flowers are insect-pollinated. Seed capsules split open and the tiny seeds are wind-dispersed. It is often stated that this plant does not normally set seed, but this is incorrect. Plants are perennial, tending to multiply vegetatively by formation of new root tubers and shoots and death of older parts. During winter food is stored in the fleshy tuberous roots. Like most orchids, the roots are infected by a fungus, called a mycorrhizal fungus, which assists the orchid in absorption of important nutrients from the soil.

    Similar species
    Within Northern Ireland there are no similar species. The autumn lady's-tresses (Spiranthes autumnalis) occurs in other parts of Ireland, and is somewhat similar, but flowers at a much later date.

    How to see this species
    The plant was not found in Northern Ireland until the 1890s, but is now known from a number of sites around Lough Neagh, Lough Beg, the Mourne Mountains, the Antrim Hills, and the shore of Upper Lough Erne. The best site to see it is probably near Church Island on the marshy western shore of Lough Beg in County Londonderry, but numbers of plants vary from year to year, and grazing by animals may make it difficult to find. In general, it prefers wet or waterlogged non-acidic fen or marsh, but plants have also been found in acidic conditions in the Mourne Mountains. Most sites are at a low altitude, but some are at up to 300 metres in hill districts. Sites are best visited between late July and the end of August.

    Current status
    Because of the ease with which this plant can be overlooked, it is difficult to assess whether the considerable number of new sites found since 1960 outside its ‘classic’ area of the Lough Neagh basin is a real expansion of the plant or the discovery of long-existing colonies. There has, however, been a real reduction in the number of sites in the Lough Neagh basin. This orchid is legally protected from uprooting or destruction under the Wildlife Order (NI), 1985.

    Why is this species a priority in Northern Ireland?
    It is a UK Priority Species - the UK holds the largest population of this plant in Europe - and Northern Ireland has about one-third of the total UK population. It also holds about 50% of the total Irish population. Outside North America, this species is only found in Great Britain and Ireland.

    Threats/Causes of decline
    There appears to have been a real reduction in the number of sites around Lough Neagh, Lough Beg and along the lower River Bann in the past forty years. This may be because of over-grazing and reduction in the water-level of the loughs. The loss of the lower Bann-side plants from the Kilrea area, where it was first discovered in 1892, can be attributed to the sites being buried under material dredged up from the river in the 1930s. A 1980 site from the Mourne Mountains has been destroyed by agricultural improvement.

    Conservation of this species

    Current action
    Some sites for this species are designated as Areas of Special Scientific Interest by the Environment & Heritage Service.

    • Most of the Northern Ireland sites lie within Areas of Special Scientific Interest

    • One site is situated within the Upper Lough Erne candidate Special Area of Conservation

    • One site lies within the North Antrim Coast candidate Special Area of Conservation

    • Two sites lie within the Lough Neagh Special Protection Area

    • The species is protected under the Wildlife (N.Ireland) Order, 1985.

    • Sites are monitored on an ad hoc basis by various groups.

    Proposed objectives/actions

    • Ensure that the species requirements are considered during reviews of relevant farming policies and agri-environment schemes.

    • Ensure that management plans for Special Areas of Conservation containing S.romanzoffiana include prescriptions for the species' conservation.

    • Restore the habitats of selected historical sites from where the species was previously recorded during the last 60 years, to encourage the recovery of these ‘extinct’ populations.

    • Publish a management plan for the conservation of S. romanzoffiana incorporating the findings of recent research projects.

    • Supply seed from a representative sample of sites to the Irish Threatened Plant Genebank for maintenance, storage and ex situ conservation.

    • Inform all landowners and local authorities of the presence of S. romanzoffiana on their lands or in their areas, and highlight the importance of this rare orchid and relevant legislation.

    • Advise landowners and local authorities of potential impacts to S. romanzoffiana that could be caused by land management practices and ensure that they are aware of the potential risks to the species that could be caused through inappropriate land management or development.

    • Monitor all sites to to ensure that optimal site management is being achieved and to determine whether viable populations are being maintained.

    • Raise awareness of the species among volunteers, botanists, professional conservation workers.

    What you can do
    Records of new sites and sizes of populations are always valuable. Send to The Botanical Society of the British Isles - c/o Department of Botany, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU or to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU Tel. 028 9039 5256

    Further information

    Flora of Northern Ireland

    UK Biodiversity Action Plan

    Species Action Plan (all-Ireland)

    Foley, M. & Clarke, S. ( 2005) Orchids of the British Isles. Griffin Press/Royal Botanic Garden Edinburgh

    Harrap, A. & S. (2005) Orchids of Britain & Ireland. A.& C. Black, London.

    Text written by:
    Paul Hackney