Northern Ireland's Priority Species

Monotropa hypopitys – yellow bird's-nest

 

Distribution map

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Monotropa hypopitys L.
Family: Monotropaceae

The yellow birdís-nest is a saprophytic species of woodland found mainly in County Fermanagh, but with isolated sites in Counties Londonderry and Antrim.

In brief

  • Mainly found in the Erne basin of County Fermanagh

  • Found in woodland

  • Can only be seen when the flowering or fruiting shoots appear in July and August

  • Northern Ireland holds the bulk of the recently recorded sites in Ireland

  • Can be readily overlooked so may be under-recorded

  • Threatened by scrub or woodland clearance.

Species description
A strange-looking herbaceous plant consisting of a globose, perennial underground stock which bears numerous fibrous roots and seasonal above-ground flowering shoots of waxy appearance. The flowering shoots are totally devoid of functional leaves and of a uniform yellow colour; grows to about 25cm in height. The tubular flowers droop downwards, but become erect in fruit. Flowering shoots may not appear every season. It is probably best described as an indirect parasite of various trees, using mycorrhizal fungi as an intermediate means of connecting to its host.

Life cycle
Flowering shoots are somewhat sporadic in their appearance. The plant may persist for an unknown number of years entirely in the form of the curious underground stock which produces numerous roots which are infected by a fungus (called a mycorrhizal fungus). The flowers are pollinated by insects and are succeeded by a round fruit capsule containing the seeds. Many books describe this plant as a saprophyte (feeding on rotting vegetable matter) but it seems probable that it is really an indirect parasite of trees, using the mycorrhizal fungus as an intermediary. This would explain why it always occurs in scrub or woodland. Germination of the seed may take place in the absence of the mycorrhizal fungus, but infection of the seedling by the fungus is required for development to maturity. The species, and perhaps genus, of fungus seem to vary according to the host tree species, but Tricholoma has been identified as one genus with which yellow birdís-nest is associated in Great Britain. There is no information on which fungi are associated with this plant in Ireland.

Similar species
There are no similar species occurring in Ireland. However, the species is divisible into two subspecies differing in chromosome number and some features of the flower. Most Irish plants seem to belong to M. hypopitys subsp. hypophygea which can be separated from subsp. hypopitys by having flowers which are hairless inside, but the distinctions between these subspecies are not always so clear.

How to see this species
The easiest places to find this plant are Straidkilly National Nature Reserve near Glenarm, County Antrim and several sites in western County Fermanagh such as Correl Glen National Nature Reserve near Derrygonnelly, Carrickreagh, Ely Lodge Forest and Castle Caldwell Forest Park around Lower Lough Erne. Look for the plant in woodland or scrub in July or August but remember that it does not always produce flowering shoots every summer at every site. Relevant access permissions should always be sought prior to visiting any sites.

Current status
The main centre of distribution is in western County Fermanagh, especially around Lough Erne and there is one site in County Antrim, near Glenarm. It was also seen once at Errigal Glen near Garvagh in County Londonderry in 1944.

Why is this species a priority in Northern Ireland?

  • This species is rare with Northern Ireland holding more than 50 per cent of the current known sites in Ireland.

It has declined throughout most of the Republic of Ireland and is now known from only 18 per cent of its former total range. It is an Irish Red Data Book species listed as rare.

Threats/Causes of decline
Woodland destruction is likely to be the only serious threat to this species, but an apparent decline could be caused by under-recording – partly the result of this plantís unpredictable flowering at some of its sites.

Conservation of this species

Current action

  • Many of the sites for this species are designated as ASSIs

  • Some sites for this species are designated as National Nature Reserves

  • Some sites lie within forests or forest parks managed by Forest Service

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

Proposed objectives/actions

  • Maintain the number of populations of this species

  • Maintain the range of this species

  • Establish appropriate management of its known sites

  • If refound at former known sites, ensure that the population is maintained.

What you can do
This species may be under-recorded. Look for it in areas of woodland, especially on limestone. Send any records to either Botanic Society for the British Isles (BSBI), 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, Tel: 028 9039 5256, cedar.info [at] magni.org.uk.

Further information

Links
http://www.bio.ic.ac.uk/research/bidartondo/pubs/NPHLeake2004.pdf

http://www.bio.ic.ac.uk/research/bidartondo/pubs/Bidartondo2005.pdf

Flora of Northern Ireland

ASSIs

Literature
Hackney, P. (1992). Stewart & Corryís Flora of the North-east of Ireland, 3rd edn. Institute of Irish Studies, Belfast.

Preston, C.D., Pearman, D.A. and Dines, T.D. (2002). New Atlas of the British & Irish Flora. Oxford University Press/DEFRA

Text written by:
Paul Hackney