Potentilla palustris (L.) Scop., Marsh Cinquefoil
Account Summary
Native, common. Circumpolar boreo-temperate.
1881-2; Barrington, R.M.; Lough Erne.
Throughout the year.
Growth form and preferred habitats
This perennial has attractive, star-like flowers, plus interesting grey-green, palmate leaves and weak stems which grow either erect or sprawling, rooting like stolons. These stems and a far-creeping woody rhizome sometimes help form floating multi-species mats of vegetation in shallow, slow-moving waters.
P. palustris is found in both very acid and very obviously calcareous mainly lowland habitats, on permanently, intermittently or seasonally flooded ground.
The species has wide ecological tolerances and it ranges from very acid, nutrient-starved, peaty sites (eg in drains and wet hollows on bogs, or in sheltered, shallow pools on lowland pastures or in upland grassy heaths) to productive, base-rich conditions, in muddy or silty soils on marshy grasslands, or in shallow, moderately acidic, but lime-rich waters around lakeshores and along the banks of slow-moving rivers. It can also tolerate semi-shade under trees in wet woodland at all levels and in willow and alder fen-carr around lakeshores.
P. palustris can be locally dominant and is very commonly associated with other rhizomatous species, including Carex rostrata (Bottle Sedge), Equisetum fluviatile (Water Horsetail) and Menyanthes trifoliata (Bogbean), in wet or flooded, poor- to medium-nutrient, acidic peaty ground. In these, and in many other situations, Marsh Cinquefoil can clearly survive competition from taller, shading plants over a wide range of organic and mineral soils.
Flowering reproduction
Since its rhizome and stolons form clonal stands, local survival of P. palustris does not require much seed production in stable habitats.
Seed is vital, however, both in terms of long-term maintenance of variation and vitality and dispersal ability to fresh sites. The dark crimson flowers, with petals half the size and much less conspicuous than the sepals, appear from May to July and are visually conspicuous. They also give off a terrible smell and their partially concealed nectar attracts insects such as craneflies, mosquitoes and stingless wasps (Proctor & Yeo 1973; Proctor et al. 1996). Unvisited flowers are self-compatible, but selfed individuals set a reduced amount of seed (Olesen & Warncke 1992). As in P. anserina (Silverweed), seeds can float for a long period, but nothing is known about their survival, transport and establishment. A clear case of further work required.
Fermanagh occurrence
Marsh Cinquefoil is very frequent, widespread and locally abundant in Fermanagh, being represented in 265 tetrads, 50.2% of those in the VC. It is most frequent in the area south of Lough Erne. It also occurs in semi-shade in wet woodland and in fen-carr around Lough Erne and, more rarely, in damp, upland woodlands on the Western Plateau.
British and Irish occurrence
Marsh Cinquefoil is widespread in most of B & I, the distribution showing a N & W preponderance. Considerable local extinction has occurred over the last 120 years, especially in the drier SE of both islands and the English Midlands (Preston & Croft 1997). Loss of habitat through drainage and agricultural improvement is largely responsible for the losses of the past 60 years (D.J. McCosh, in: Preston et al. 2002).
European and world occurrence
P. palustris is a member of the circumpolar boreo-temperate group and is common throughout arctic and boreal regions around the northern hemisphere and extends south to C Spain, N Italy and S Bulgaria, but is absent from the Mediterranean shores and islands (Kurtto et al. 2004, Map 3390).
Uses
The attractive, dark crimson, star-like flower and the interesting grey-green, palmate leaves makes this a garden-worthy plant, or almost so, were it not for its far-creeping, invasive woody rhizome. Having said this, it is obviously suitable for larger gardens with aquatic features and a white-flowered form also exists in the horticultural trade (Griffiths 1994).
Threats
In Fermanagh, increasing nutrient levels from agricultural runoff and atmospheric nitrogen pollution might oust this species from previously mesotrophic habitats, especially around our larger lowland lakes.