Pimpinella saxifraga L., Burnet-saxifrage

Account Summary

Growth form and preferred habitats

This wintergreen, deeply rooted, semi-rosette perennial arises and grows erect from a stout rootstock. Burnet-saxifrage prefers well-drained, dry to damp, often shallow calcareous or base-rich soils supporting unproductive, short-turf grassland, such as occurs in old, lowland, species-rich, hay-meadows, pastures, roadsides verges and riverbanks. In Fermanagh, similar unproductive rough grassland habitats often lie close to many of the county lakeshores, although P. saxifraga is definitely neither a wetland nor a woodland species, or even one tolerant of more peaty, acidic conditions. It can sometimes be found elsewhere in B & I, however, in more acid soils of low fertility in older low-lying grassland sites and in rocky habitats, especially those on calcareous or other basic rocks. P. saxifraga can grow in full sun or half-shade and it prefers warmer soils. It can grow and survive in dry, but not severely droughted situations thanks to a deeply penetrating taproot (Sinker et al. 1985; Grime et al. 1988, 2007; Rich et al. 1996).

P. saxifraga is low-growing, stems (15-)30-100 cm tall, and it tends to lack the ability to withstand competition in both fertile soils and moderately disturbed habitats. The established strategy of the species is described as intermediate between a Stress-tolerant Ruderal and a more general ability C-S-R (Competitor-Stress-tolerant-Ruderal) species. Essentially, P. saxifraga is only able to compete successfully in short turf situations, where taller, more vigorous species are restrained by less favourable growing conditions, whether that be determined by soil nutrients, moisture, depth, or other factors such as shade or disturbance level.

Burnet-saxifrage has a low colonising ability and is considered a useful indicator species of old species-rich grasslands, especially old calcareous grasslands that have not been heavily disturbed, ploughed or re-sown, a greatly diminished vegetation type that remains extremely threatened (Grime et al. 1988, 2007; Braithwaite et al. 2006).

Flowering reproduction

The plant is only conspicuous between July and September when flowering and fruiting, since the very variable leaves are 1-2 pinnate and are held low on the stem, around 10 cm from the ground, while by contrast the flowering stem can reach up to 1.0 m in height. The basal leaves wither early and often are not present when the plant flowers, their role being taken over by a small number of stem leaves.

The inflorescence is a compound umbel of 10-22 rays bearing small, white or rarely pinkish flowers, the outer petals not radiating. The peduncle is longer than the rays and the majority of the 100 plus flowers per inflorescence are hermaphrodite (bisexual), although not perfect since they lack sepals. Pollination is by insects (Hymenoptera, bees), attracted by openly presented nectar (Fitter 1987). Fruits are produced quite late in the growing season in August and September, each being a schizocarp, 2-3 mm, ovoid, laterally compressed, and the two mericarps each have slender ridges, paler than the reddish-brown vittae between them (Tutin 1980; Sell & Murrell 2009).

Seed (ie mericarp) of P. saxifraga can survive passage through the complex alimentary canal of cattle, remaining viable when cast in dung, thus achieving a limited degree of local secondary dispersal (Salisbury 1964).

Being a deep-rooted perennial species, individual plants of Burnet Saxifrage are capable of surviving in unmown meadow grassland for many years as Tamm (1956) showed in C Sweden. In permanent quadrats compared over a twelve year period, Tamm found that one individual or clone of P. saxifraga persisted and grew substantially, although five other clones disappeared. Only one small individual was recruited anew to the plots during the long period of observation (Tamm 1956, Fig. 12).

Variation

There is considerable variation within P. saxifraga and Sell & Murrell (2009) list three subspecies and five varieties of one of them (subsp. saxifraga). The other two subspecies are: subsp. alpestris (Spreng.) Vollm. and subsp. nigra (Mill.) Gaudin.

Irish and Fermanagh occurrence

In Ireland, P. saxifraga is very noticeably much more frequent in the drier and warmer S & E of the island than elsewhere. While it is recorded at the coast from the very northern tip of Ireland near Malin Head in Co Donegal (H34) and also occurs locally on the basalt scarps of Co Antrim (H39) (FNEI 3), Fermanagh appears to be close to the NW limit of this species for Irish inland sites. It strikes the current author (RSF) that the occurrence and unusual Irish distribution pattern of this species is most similar to that of Primula veris (Cowslip), another plant near its natural limits in Fermanagh.

While the Fermanagh Flora Database contains records of P. saxifraga from eight tetrads, there are only five post-1986 records at four widely scattered sites and RHN and the current author consider it very rare in the VC.

Another occasional habitat P. saxifraga occupies is in drier parts of old disused quarries, such as one at Clonmackan in SE Fermanagh, near Clones in Co Monaghan (H32). It was first found here by Meikle and co-workers in 1951 associated with Daucus carota (Wild Carrot), Anagallis arvensis (Scarlet Pimpernel), Centaurium erythraea (Common Centaury) and four orchid species including Anacamptis pyramidalis (Pyramidal Orchid) and Ophrys apifera (Bee Orchid). RHN found it again nearby at Clonmackan bridge in 1990 and the only other recent records are from Belleek village (1987) and from limestone meadows south of Clonatty Bridge (1991 & 2003) where, incidentally, Primula veris (Cowslip) is also recorded.

Meikle and co-workers discovered Burnet-saxifrage in limestone sites at Knockmore and the Marble Arch (Meikle et al., 1957), but later very detailed surveys of these areas have not seen it. Possibly the species is being overlooked and its status is worth further careful investigation.

British occurrence

P. saxifraga is widespread in Britain, except NW of the Great Glen in Scotland, the overall pattern again, to some extent, mirroring the distribution in the warmer S & E of Ireland (New Atlas).

European and world occurrence

Burnet-saxifrage is also widespread in most of temperate Europe, although thinning northwards. It is also indigenous in SW Asia and is a rare introduction in eastern N America and New Zealand (Hultén & Fries 1986, Map 1394).

Uses

The Modern Herbal (Grieve 1931) appears a little confused and confusing regarding the medicinal uses of the three Burnets and especially regarding Burnet-saxifrage which ends up with two entries in the work (pp. 146 & 720). The leaves and roots of the plant are used by herbalists, the whole herb being collected in July and dried.

The root is described as very hot and acrid, burning the mouth like pepper, although on drying and ageing pungency is considerably diminished. It contains a bitter resin and a blue coloured essential oil, both being useful to relieve flatulent indigestion. The fresh root chewed promotes the flow of saliva and is recommended for easing toothache and paralysis of the tongue. A decoction is said to dissolve mucus and is used as a gargle to treat hoarseness and throat infections. It is also prescribed for asthma and dropsy.

Small bunches of the leaves and shoots tied together and suspended in a cask of beer impart to it an agreeable aromatic flavour and are also thought to correct tart or spoiled wines.

Cows that graze the plant are thought to have an increased milk flow (Grieve 1931, p. 720). Other modern herbals mention its use as a wound dressing to stop bleeding and prevent infection. It is also said to be used to treat fever, gout and rheumatism (Darwin 1996). As an astringent, Burnet-saxifrage was said to be used for cleansing of freckles, although Allen & Hatfield (2004) voice their considerable scepticism.

Names

The genus name 'Pimpinella' is of obscure derivation, possibly from the medieval Latin 'bipinella' meaning '2-winged', referring to the simply pinnate arrangement of the leaflets (Hyam & Pankhurst 1995). The name was first used by the Italian herbalist, Matthaeus Sylvaticus in the early 14th century in his pharmacopoeia published under the Latin title Pandectarum Medicinae or Pandectae Medicinae (Encyclopedia of Medicines) (Gilbert Carter 1964).

Grigson (1974) has it that the 15th century name of the plant was 'pympernol' or 'pympernelle' (modern 'pimpernel'), derived from the French 'pimprenelle' or Old French 'piprenelle', from medieval Latin 'pipinella', derived ultimately from Latin 'piper' meaning 'pepper', owing either to the taste of the leaves of P. saxifraga or the resemblance of its ripe fruits to peppercorns. The Latin specific epithet 'saxifraga' is from 'saxum', a rock, and 'frango', to break. In herbal medicine, it was supposed to be capable of breaking up a stone in the bladder (Stearn 1992).

The English common name 'Burnet-saxifrage' is derived from a resemblance of the basal or root leaves to the pinnate leaves of Sanguisorba officinalis (Great Burnet) and Poterium sanguisorba (Salad Burnet). The flowerheads of both the latter named are a dark crimson-brown or mahogany, or 'burnet', from the Old French 'burnete', or 'brunet'), becoming French 'brunette' (Grigson 1974). 'Burnet' is a term previously applied to a brown cloth and it was given to the two plants on account of their brown flowers (Prior 1879). As Mabey (1996) points out, 'Burnet-saxifrage' is a rare example of a plant named after two other unrelated families: 'burnet' from the shape of the leaves, and 'saxifrage' from its traditional herbal use in treating kidney and bladder stones.

Threats

P. saxifraga populations have suffered a rapid and severe decline due to the widespread destruction of old calcareous, neutral and acidic grasslands across B & I associated with intensification of agriculture since the 1950s and the eutrophication of many previously suitable habitats which encourages tall, ranker swards in which Burnet-saxifrage cannot compete or survive (Braithwaite et al. 2006).

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