Biology
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This orchid produces its beautiful flowers in July and August. Despite the fact that the plant flowers regularly, no cross-pollination has ever been confirmed in this country and no seed has yet been recorded. It is still not clear how Irish lady's tresses reproduces in the UK and Ireland, although recent genetic research has suggested that the northern populations of Scotland have reproduced sexually in the recent past. The plant also seems to reproduce vegetatively, although again it is not clear how.
Conservation
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Irish lady's tresses is listed in the UK Biodiversity Action Plan and is included in Plantlife's Back from the Brink conservation programme. A survey in 1995 - 1996 by the Royal Botanic Gardens, Edinburgh for Scottish Natural Heritage, turned up more specimens of this species than were previously thought to exist. Although the UK sites represent the entire European population of this species, at present just under half of its sites in Scotland have statutory protection. It is therefore of paramount importance that the sites are protected and their management, and that of the surrounding land, is altered to suit the species.
Part of the plan to preserve this species is to encourage more landowners, on whose property the flower grows, to adopt more traditional grazing regimes that would benefit this plant, hopefully supported by one of the agri-environment schemes designed to help many of our threatened plants. It is also likely that studies will also be carried out to discover why the UK's plants do not seem to be able to cross-pollinate and produce seed. This will involve studies of populations in Ireland and Northern Ireland, as well as the populations of this lovely orchid in North America.
Description
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This beautiful orchid has white flowers that climb up the stem in three closely woven spirals. The leaves are clustered around the base of the stem and resemble those of grass. The group of orchids known as 'lady's tresses' are believed to have been so-named from the resemblance of the spiral florets to locks of braided hair.
Habitat
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Irish lady's tresses is a plant of wet marshy ground, wet meadows near water bodies and bogs. It prefers nutrient poor soil, especially that which is flooded at intervals, and often occurs on grazed meadows in open sedge-rich lawns.
Range
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The European range of this orchid covers western Scotland, Northern Ireland and the Irish Republic. There is also one site in south Devon. However, the chief home of the Irish ladies' tresses is North America. It is possible that the British and Irish plants originate from refugia in the Hebrides and Ireland as the glaciers retreated about 8000 years ago, after the last Ice Age.
Status
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Classified as Near Threatened in Northern Ireland, and protected under Schedule 8 of the Wildlife (NI) Order.
Threats
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Irish lady's tresses is an important plant as the UK populations are the only remaining examples of the species surviving in Europe. Although the UK BAP lists the use of fertilisers and herbicides as possible threats, the main threat seems to be too little or a lack of grazing in Scotland, which allows taller competitive vegetation to invade the sites.
Associations
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In Great Britain and/or Ireland:
Plant / pollenated
adult of Bombus hortorum pollenates or fertilises flower of Spiranthes romanzoffiana
Other: major host/prey
Plant / pollenated
adult of Bombus pascuorum pollenates or fertilises flower of Spiranthes romanzoffiana
Other: major host/prey
Comments
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Plants of Spiranthes romanzoffiana vary considerably in habit but are usually quite consistent in floral morphology. The strongly hooded, ascending flowers with abruptly reflexed lips provide a distinctive geometric precision. The pandurate lip with typically three veins, the lateral with abruptly wide-spreading branches, is a key feature. In some areas, however, especially at the edges of the range of the species, some variation is apparent and is sometimes coincident with variability in ploidy level. In particular, in California and adjacent southwestern Oregon variability reaches its peak, with plants variously exhibiting yellowish flowers, loosely spiraled inflorescences, and spreading lateral sepals. Some of this variation may result from gene flow from S. porrifolia, but with various ploidy levels common in this area, even within populations, the situation is apparently more complex than simple hybridization.
Hybrids of Spiranthes romanzoffiana with S. lacera var. lacera are known as S. × simpsonii Catling & Sheviak.
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Description
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Plants 8–55 cm. Roots few–several, spreading to descending, tuberous, mostly to 1 cm diam. Leaves persisting through anthesis or fugaceous, basal, often on proximal portion of stem, ascending to spreading, linear to linear-lanceolate, elliptic, or oblanceolate, to 26 × 3 cm. Spikes usually very tightly spiraled, 3 flowers per cycle of spiral, rarely loosely spiraled or with more than 5 flowers per cycle; rachis glabrous to very sparsely pubescent, capitate glands short-stalked or often sessile (longest trichomes 0.03–0.18 mm). Flowers ascending, white to ivory, rarely yellowish white, tubular; sepals and petals connivent, forming hood above abruptly reflexed lip; sepals connate at base, 5.3–12.5 mm; petals linear to ovate, apex obtuse to subacute; lip pandurate, 4.8–10.2 × 1.6–6.8 mm, base broadly expanded, apex broadly dilated, separated by narrow isthmus, apical dilation variable, rarely lip nearly ovate, glabrous or with a few scattered trichomes on adaxial surface; veins typically 3, branches wide-spreading; viscidia linear-lanceolate; ovary 2–7 mm. Seeds monoembryonic. 2n = 44, 66, 88.
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Distribution
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Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Sask., Yukon; Alaska, Ariz., Calif., Colo., Conn., Idaho, Ill., Ind., Iowa, Maine, Mass., Mich., Minn., Mont., Nebr., Nev., N.H., N.Mex., N.Y., N.Dak., Oreg., Pa., S.Dak., Utah, Vt., Wash., Wis., Wyo.; Europe (Great Britain, n Ireland).
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Flowering/Fruiting
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Flowering Jun--Sep(--Oct).
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Habitat
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Moist to wet meadows, tundra, marshes, fens, prairies, stream banks, seeps, coastal bluffs, dunes; 0--3400m.
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Synonym
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Gyrostachys stricta Rydberg; Ibidium strictum (Rydberg) House; Spiranthes stricta (Rydberg) A. Nelson
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Spiranthes romanzoffiana
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Spiranthes romanzoffiana, commonly known as hooded lady's tresses[1] (alternatively hooded ladies' tresses[2]) or Irish lady's-tresses[3] (Irish: Cùilìn Gaelach), is a species of orchid. Collected by Chamisso during the Romanzov expedition it was described by him in 1828 and named for Count Nikolay Rumyantsev who financed the expedition. This orchid is native to North America, Ireland and the British Isles.[4]
Spiranthes romanzoffiana
. a, base of plant, showing linear leaves and fleshy roots, x %; b, spike, x 1%; c, single whorl of flowers; x I'f,; d, flower, lateral view, X 4; e, flower (longitudinal section), x 4; f, back of column, showing anther, x 6; g, front of column, showing stigma, x 6; h, lower lip, x 6. Original plate
Description
Hooded lady's tresses is a perennial plant with a fleshy rootstock. It sends up shoots with lanceolate leaves and three rows of flowers arranged in spirally twisted rows. Each scented flower has the sepals and petals united forming a lip of a tube. The labellum (or lower petal) of the flower is white with green veins.[5][6]
The plant flowers in late summer. The flowers are pollinated by insects, and the tiny dust-like seed is distributed by the wind. However the plant can also reproduce vegetatively by means of root tubers which can grow new shoots while the old parts of the plant die. The orchid is associated with a mycorrhizal fungus which can provide it with essential nutrients.[6]
Distribution and habitat
Hooded ladies' tresses was first described by the German botanist Adelbert von Chamisso. He named it in honour of his patron Nikolay Rumyantsev who had financed the scientific exploration to the Americas in 1815–1818 on which he found the orchid. It is common in North America, including Canada and the United States, but also grows in a few locations in Scotland and Ireland.[2] It is now considered regionally extinct in England, but has recently (2019) been found in Wales.[7] The first Irish record was made in 1810 in County Cork.[8] Since then it has been found in a number of other locations in Ireland and Northern Ireland, including the Lough Neagh basin and the Mourne Mountains and the hills of Antrim.[6] It grows along lakeshores and in damp pastures.[5] The distribution pattern, occurring on both sides of the Atlantic Ocean, is puzzling.[9]
Ecology
Interactions between Irish Lady's Tresses and Its pollinating partners have only been studied in the West Irish populations.[10] The most common pollinators are the Bombus pascuorum, B. hortorum and Apis mellifera.[10] Studies on Mycorrhizal associations for Irish Lady's Tresses have not been conducted. Recent studies have found genetic hybrids in the Ontario, Canada population.[11] Genetic studies have also been conducted in order to ascertain the genetic adversity of the European Population.[12]
References
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^ USDA, NRCS (n.d.). "Spiranthes romanzoffiana". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 27 November 2015.
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^ a b "Spiranthes romanzoffiana (Hooded Ladies' Tresses)". goorchids.northamericanorchidcenter.org. Go Orchids. Retrieved 2018-11-09.
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^ BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
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^ "World Checklist of Selected Plant Families".
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^ a b Parnell, J. and Curtis, T. 2012. Webb's An Irish Flora. Cork University Press. ISBN 978-185918-4783
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^ a b c "Spiranthes romanzoffiana – Irish lady's-tresses". Northern Ireland Priority Species. Retrieved 19 March 2020.
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^ "GB Red list for vascular plants (revised 2019)". Botanical Society of Britain & Ireland. 2021. Retrieved 11 March 2022.
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^ Hackney,P. Ed. 1992. Stewart & Corry's Flora of the North-east of Ireland. Third edition. Institute of Irish Studies, The Queen's University of Belfast ISBN 0-85389-446-9
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^ Dunn, Jon (2018). Orchid Summer: In Search of the Wildest Flowers of the British Isles. Bloomsbury Publishing. pp. 389–392. ISBN 978-1-4088-8090-6.
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^ a b Duffy, Karl (January 2008). "The Effects of Plant Density and Nectar Reward on Bee Visitation to the Endangered Orchid Spiranthes Romanzoffiana". Acta Oecologica. 34 (2): 131–138.
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^ R. C, Simpson (January 1978). "Spiranthes Lacera Var. Lacera X S. Romanzoffiana, a New Natural Hybrid Orchid from Ontario". Canadian Field-Naturalist. 1 (1): 350–358.
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^ Hollingsworth, Peter (December 2003). "Population Genetic Structure in European Populations of Spiranthes Romanzoffiana Set in the Context of Other Genetic Studies on Orchids". Heredity. 92: 218–227.
- Correll, D.S., Native Orchids of North America, p. 220. 1978.
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Spiranthes romanzoffiana: Brief Summary
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Spiranthes romanzoffiana, commonly known as hooded lady's tresses (alternatively hooded ladies' tresses) or Irish lady's-tresses (Irish: Cùilìn Gaelach), is a species of orchid. Collected by Chamisso during the Romanzov expedition it was described by him in 1828 and named for Count Nikolay Rumyantsev who financed the expedition. This orchid is native to North America, Ireland and the British Isles.
Spiranthes romanzoffiana. a, base of plant, showing linear leaves and fleshy roots, x %; b, spike, x 1%; c, single whorl of flowers; x I'f,; d, flower, lateral view, X 4; e, flower (longitudinal section), x 4; f, back of column, showing anther, x 6; g, front of column, showing stigma, x 6; h, lower lip, x 6.
Original plate
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