A stoloniferous perennial herb found in wet, base-rich flushes and mires, especially where the vegetation is checked by grazing. Formerly near sea level, it survives now only in its upland localities usually at 300-650 m, but reaching 750 m (Mickle Fell, N.W. Yorks.).
The 1962 Atlas showed a decline up to about 1930, with lowland populations (mostly in Scotland) disappearing owing to afforestation, drainage and other demands of agriculture. Since then, however, there has been only a slight reduction in the number of 10-km squares.
Circumpolar Boreo-arctic Montane element.
Count of 10km squares in Great Britain: 20
Count of 10km squares in Ireland: 16
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: -0.3
RDB Species Accounts
Saxifraga hirculus L. (Saxifragaceae)
Yellow marsh saxifrage, Moran Rèisg
Status in Britain: VULNERABLE. WCA Schedule 8. EC Habitats & Species Directive, Annexes II, IV.
Status in Europe: Vulnerable.
S. hirculus is a plant of base-rich flushes and mires. Though at one time occurring from near sea-level, all its lowland habitats have been lost, and it is now a montane plant, ascending to 800 metres. In the species-rich flush and mire communities where S. hirculus occurs, sedges such as Carex echinata, C. flacca, C. panicea or C. viridula ssp. oedocarpa are usually prominent, together with a wide array of other associates including Holcus lanatus, Lychnis flos-cuculi, Montia fontana, Parnassia palustris, Pedicularis sylvatica, Ranunculus flammula, Sagina nodosa, Sedum villosum, Selaginella selaginoides, Triglochin palustre, Viola palustris, and robust mosses such as Bryum pseudotriquetrum, Drepanocladus revolvens, Palustriella commutata and Philonotis fontana (Eddy, et al. 1969). It also grows in taller open mesotrophic mires in which Carex rostrata, Juncus acutiflorus and Sphagnum species may be common.
It is a rhizomatous perennial, producing slender upright flowering shoots and creeping runners. Some rhizomes do not produce flowering shoots in some years, but there are normally between one and five runners. Flowering is relatively late in the season, extending from July to September. The flowers are bright-yellow, insect-pollinated and normally protandrous. In studies of Danish populations, most insect visitors were hoverflies. A high proportion of seeds are viable.
In Britain, S. hirculus was known in twelve vice-counties in the nineteenth century, eight in Scotland and four in northern England. It has become extinct in several vice-counties, mostly in Scotland, and its main stronghold is now a 50 km-long section of the northern Pennines between Stainforth and South Tyne and Weardale. Within this block the total population probably exceeds 50,000 plants, and several localities have thriving populations of more than 1,000 flowering shoots (Taylor 1987a). Together these represent 80-90% of the British population. It may still occur at some Pennine sites for which there are only pre-1987 records. In Scotland four sites remain, one in Midlothian and three in Aberdeenshire (Welch 1970; 1992). The two largest populations (in the latter county) held nearly 300 and 485 plants in 1995. Further details on its habitats and status in Scotland are given in Welch (1995).
Its sites are often heavily grazed, and probably because of its low stature, S. hirculus seems unable to survive in fens and mires with tall vegetation. Sheep graze the flowers and reduce seed output, but they check other plants, so that moderate levels of grazing are probably beneficial. In Scotland, some sites where S. hirculus has disappeared still seem suitable, and the reasons for its disappearance are unclear. Drainage, afforestation and land claim for intensive agriculture are the main threats to existing populations. Flowers are often scarce because of grazing, and the plant is often a shy flowerer. This, together with the similarity in the colour of the flowers to Leontodon autumnalis and Ranunculus flammula which are often abundant in flushes, has given S. hirculus a reputation of being elusive. Furthermore, the entire leaves can be difficult to distinguish from those of Ranunculus flammula and Epilobium palustre without close scrutiny.
S. hirculus varies markedly in morphology across its range, and four subspecies are now recognised (Hedberg 1992). As far as it is known, only ssp. hirculus, the most widely-distributed subspecies, occurs in Britain.
This plant is widely distributed in Europe, but is declining or threatened in most countries. It is endangered in Germany, Switzerland, Ireland, Poland and Lithuania, vulnerable in Estonia, Latvia, Norway, Denmark, and rare in Turkey. It also occurs in the Caucasus, Himalayas, and has a circumpolar range in Asia and North America.
PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.
Atlas text references
1988. The Irish Red Data Book. 1. Vascular Plants.
1992. Taxonomic differentiation in Saxifraga hirculus L. (Saxifragaceae), a circumpolar Arctic-Boreal species of Central Asiatic origin. Botanical Journal of the Linnean Society. 109:377-393.
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1999)
1965. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
1989. Saxifrages of Europe.
1999. British Red Data Books. 1. Vascular plants, edn 3.