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Pyrola minor L., Common Wintergreen

Account Summary

Native, rare. Circumpolar boreo-temperate.

1904; Praeger, R.Ll.; scarp south of Carricknagower Lough.

Throughout the year.

Growth form and preferred habitats

An evergreen, mycorrhizal, patch-forming perennial herb with a creeping rhizome and thick, rather leathery, roundish-oval, radical leaves borne in a rosette at the base of the very short, woody stem. It occurs in damp woods, both deciduous and coniferous, including plantations, on a variety of humus-rich soils, usually covered with a deep surface litter. It can also occur on damp upland heaths and on shady ledges on wet, rocky scarps. Members of the genus all have mycorrhizal roots and, although they are capable of photosynthesis, they can be thought of as semi-saprophytic, being able to tolerate or endure conditions of very deep shade (Salisbury 1942). Unlike P. media (Intermediate Wintergreen) and Orthilia secunda (Serrated Wintergreen) which in Fermanagh are generally either completely vegetative or very shy flowering, most populations of P. minor in the VC usually contain quite a few flowering spikes, which aids both the discovery and the identification of the plant.

Flowering reproduction

The pinkish-white, pendulous, globular, 6 mm flowers are borne in a dense terminal raceme around a 10-30 cm scape from June to August. Although there is no nectar, a sticky fluid that insect visitors lick is exuded by the five lobed stigma. The straight 1-2 mm style is included within the five quite free, rounded petals of the corolla and is shorter than the stamens and ovary. The flowers are either insect- or self-pollinated and produce large numbers of very minute, lightweight (orchid-like, but even smaller) seeds, shortly tailed at each end, in a globular capsule that eventually splits to release them on any passing breeze (Melderis & Bangerter 1955; Clapham et al. 1987). As the seeds have practically no food reserves, successful germination and seedling growth appears to require the obligate assistance of a saprophytic fungal partner from the soil flora, in the same manner as terrestrial orchids do (Salisbury 1942, p. 94).

Fermanagh occurrence

In Fermanagh this pretty flowering herb grows in quite sizeable clonal patches in damp, old, mixed deciduous woodland, in a coniferous plantation and on wet, shaded scarps. Colonies can still be impressive, some producing hundreds of flower spikes and covering several square metres of shaded ground. P. minor has been recorded in a total of six tetrads in Fermanagh, all of which contain post-1975 records. Of the three pre-1951 stations, two survive, ie Florencecourt plantation and the Correl Glen woods, and four completely new sites have been discovered since 1985. The population in the Correl Glen mixed oak wood recorded in 1946 by Meikle and his friends was only rediscovered by RHN & HN in 2004, although this excellent site has been exhaustively worked botanically and has for many years been protected and recognised as one of our most important Nature Reserves. Since the plant produces huge numbers of tiny, dust-like seeds which allow the possibility of jump dispersal effected by wind, the species could very well turn up at more new sites.

In a paper entitled Among the Fermanagh hills describing five days in July 1904 spent botanising in the county, Praeger (1904) conveys the excitement he felt on finding three Pyrola species growing together on the wooded scarp south of Carricknagower Lough. The species were Pyrola secunda (= Orthilia secunda) (Serrated Wintergreen), P. media (Intermediate Wintergreen) and P. minor. Praeger knew he was only the second botanist in Ireland to ever have found such a site, the other fortunate recorder having been Dr Moore of the Glasnevin Botanic Garden, Dublin when the latter visited Co Londonderry (H40), 70 years previously! Unfortunately, despite prolonged, careful searching, we have not been able to rediscover P. minor at Praeger's Carricknagower site.

With the exception of Dryas octopetala (Mountain Avens) and P. minor, all the associated rare or scarce plant species which Praeger mentioned in his impressive 1904 paper, including P. media, Orthilia secunda and Asplenium viride (Green Spleenwort), are still to be found today where he described them. Indeed, we find the absence of Praeger's station for P. minor at Carracknagower so odd, that despite his achievements, reputation and towering stature among Irish naturalists, it is tempting to suggest he might have been mistaken – not in his identification of the plant, but rather in his recollection of the location of his discovery.

The record details additional to the first record are: Correl Glen, 1946, MCM & D; Florencecourt plantation, 1950, MCM & D; conifer plantation, Cassidy Td, Necarne estate, 28 June 1987, D. Irvine & RHN; Pollaphouca Waterfall, 26 October 1992, RHN & F. Carroll; Derryvore Oakwood, opposite Crom Castle, Upper Lough Erne, 4 January 1995, RHN, HJN & I. Herbert; wooded scarp, Pollaphouca cliffs (different grid reference from waterfall), 24 May 1998, RHN.

Irish occurrence

The New Atlas hectad map indicates that in Ireland, Common Wintergreen is a rare and slowly declining species, increasingly confined to widely scattered sites in the northern quarter of the island.

British occurrence

P. minor has a strongly marked northern distribution in Britain, being rare, widely scattered and in decline in most of SW, S & C England, East Anglia and Wales since before the 1930s. It is much more frequent and widespread in N England and Scotland, although even here it is absent from the Outer Hebrides, Orkney and Shetland (Garrard & Streeter 1983; Preston et al. 2002; Sell & Murrell 2014).

European and world occurrence

P. minor is widespread and circumpolar in the boreal regions of the N Hemisphere and is also common in montane situations further south, reaching the mountains of C Spain, C Italy and Greece and in N America stretching from Alaska south to California and east to Labrador and New England (Hultén & Fries 1986, Map 1436; Sell & Murrell 2014).

Threats

Forestry operations and overgrowth by brambles and Rhododendron at the coniferous plantation site near Necarne.