Northern Ireland's Priority Species

Orthilia secunda – serrated wintergreen

 

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.

 

Orthilia secunda (L.) House
Family: Pyrolaceae

In Ireland Orthilia secunda (sometimes referred to as Pyrola secunda), has always been a scarce, inconspicuous and very easily overlooked, creeping evergreen perennial. It appears to have declined further during the last half-century in Britain and Ireland. The main presence is in the Scottish Highlands and northern regions, while further south in Great Britain, and especially in Wales and Ireland, it appears to be in retreat.

In brief

  • This is a northern woodland and montane heathland species in Europe, Asia and North America

  • Nowadays on the southern margins of its distribution in the British Isles, it is a 'relict species' just managing to survive from earlier much more suitable, cooler climatic conditions when it would have been common in Pinewoods

  • In Northern Ireland it has been recorded in counties Fermanagh and Antrim

  • In Ireland it usually grows in acid, moist, humid, but well-drained conditions, on cliffs and in heathland under heather and bilberry scrub

  • A slender, creeping underground stem allows the basal leaf rosettes to form patches, but often only a few shoots produce flowers between June and early August

  • Grazing by sheep and goats and heather burning are factors probably responsible for much of the decline into rarity

  • In view of its unspectacular flower and very retiring nature, serrated wintergreen might still be found in other suitably damp, reasonably undisturbed heathland, cliff or scree-slope sites elsewhere in the north of Ireland.

Species description
The plant is 10 to 20cms tall, or less. The bell-shaped, pendulous flowers are white to greenish-white with the white stigma protruding. In midsummer the flowers form a terminal spike with each blossom arranged along one side of the flowering stem. The evergreen oval leaves form a loose, irregular basal rosette. The leaf margin is very finely toothed. When one has got one's eye in for the plant, the rather pale, grey-green, finely and regularly toothed, wintergreen leaves can be picked out amongst other foliage and moss all year round.

Life cycle
Flowers are sparingly produced from June to early August, and fruiting in August and September. They attract bumblebees which collect nectar and pollen, but the ability to self-fertilize is probably very important in this species, since general observation suggests insect visitors are rare in the damp, shaded upland habitats in which the plant grows. Very little published work exists specific to serrated wintergreen biology or population ecology, but a Russian study suggests seed is only transient in the soil (Thompson et al., 1997).

Similar species
The one-sided inflorescence of serrated wintergreen is distinctive. It is smaller and more delicate than other native wintergreen species, members of the closely related genus Pyrola.

How to see this species
The habitat of its only Republic of Ireland site in County Offaly was destroyed by peat-cutting, and nowadays it is rare and never abundant in just a few scattered stations in Northern Ireland. It is very local in western Fermanagh, where it grows in rock crevices, on ledges of upland scarps and scattered on steep, moist, mossy, heather and bilberry-clad, scree slopes below these cliffs on the Lough Navar plateau. The typical habitat throughout the extensive world range of the species is under conifer or deciduous woodland canopy (pine or birch), or under ericaceous heaths in mountains further south. Although we do not have a definite tree-line as such, in Fermanagh it also occurs in this 'montane' manner under the protection of low-growing heather and bilberry sub-shrubs. The steepness of cliffs and screes helps keep sheep browsing to a minimum, and our damp climate reduces firerisk. It flowers between June and early August, but flowers only sparingly here, that is, less than 10 per cent of leaf rosettes bear an inflorescence. Relevant access permissions should always be sought prior to visiting any sites.

Current status
Serrated wintergreen is a very rare and vulnerable plant species confined on the island to only a few stations in Northern Ireland. It has been recorded during the post-1986 period in only two 10km squares in counties Antrim and Fermanagh, and in another square in Londonderry during the 1970 to 1986 period. The chance exists that further relatively undisturbed sites might have the plant present, although there could be as few as one or two individuals present.It is listed on Schedule 8 of the Wildlife (Northern Ireland) Order 1985.

Why is this species a priority in Northern Ireland?

  • This species is in decline and is rare.

Threats/Causes of decline
Grazing pressure from sheep and goats and damage to heaths through peat-cutting, and more especially, the use of fire to manage heather cover, are factors probably responsible for some or most of this species decline. The natural absence of conifer canopy until recent plantation during the last century, and the previous supremacy of deciduous woodland lasting for hundreds of years, which appears less suitable for this species, must also have been a negative factor influencing the long-term survival of this, and possibly of all species of wintergreen. Being essentially a northern forest species, the current global climatic warming poses a very real danger to the long-term survival of this species in both Britain and Ireland.

Conservation of this species

Current action

  • Areas of the scarps which are its local headquarters in Western Fermanagh are protected by their ASSI status.

Proposed objectives/actions

  • Maintain the number of viable populations of the species.

What you can do
Records of new sites and estimates or counts of the sizes of populations are always valuable. Send to The Botanical Society of the British Isles – c/o Botany Department, 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, cedar.info [at] magni.org.uk, Tel: 028 9039 5256.

Further information

Links
Flora of Northern Ireland

http://www.ehsni.gov.uk/area_interest_sitesview?SiteNo=ASSI201

Literature
Illustrations in: Gibbons, B. and Brough P. (1992). The Hamlyn Photographic Guide to the Wild Flowers of Britain and Northern Europe. Hamlyn, London.

Fitter, R., Fitter, A. and Blamey, M. (1996). Collins Pocket Guide: Wild Flowers of Britain and Northern Europe. HarperCollins, London. (and many other editions).

Thompson, K., Bakker, J.P. and Bekker, R.M. (1997). The soil seed banks of North West Europe. Cambridge University Press, Cambridge.

Text written by:
Dr Ralph Forbes