Place: Texas Bar
Forming extensive mats by, to some extent, prostrate and rooting branches. Detached branches can root and lead to new individuals, but experimental propagation show large variation in rooting ability (20–90%, Hagen 2002). The main reproduction is by seeds. The species is insect-pollinated and commonly visited by small flies. Probably a mixed mater. Germinability of seeds is 60–70% at 18–20°C, but only 2% under natural outdoor conditions on a moraine (Alsos et al. in prep.; Müller et al. 2011). No special adaptation to seed dispersal. However, capsules have apical opening which ensures that the seeds only are dispersed at a minimum wind speed. Seed dispersal is often after the first snow fall, which increases the dispersal distance as the seeds are blown across a smooth surface (Savile 1972). Seeds are also dispersed by animals, e.g. geese that selectively feed on seed capsules (Prop et al. 1984). Secondary dispersal by water or wind.
This is the only Saxifraga in Svalbard with purple flowers, and non-flowering individuals are also easily distinguished by their sessile, thick, and usually triangular (at least close to the apex of the shoots) leaves.
Not thermopilous. Occurring in a wide range of environments, such as heaths and meadows, river and sea terraces, river bars, patterned ground, tussocks in mires, cliffs, and scree. Often dominating along with Dryas ocotopetala in semi-dry heath vegetation. On well to poorly drained, mixed or fine textured soils with weakly acidic to basic reaction. Occurring in moderately exposed sites with wind abrasion (plants then often tussocky), to rather protected moderate snow beds with shortened growing season (plants then mostly procumbent). Probably not much grazed by reindeer or geese.
The total range of Saxifraga oppositifolia is wide, including the entire circumarctic area and many temperate mountain ranges south to the Alps, Central Asia, and the central Rocky Mountains (Hultén 1973; Hultén & Fries 1986). A suggestion has been made to separate between pulvinate and prostrate plants as races (Andersson & Hesselmann 1901; Rønning 1996), respectivelly as ssp. reptans (G. Andersson & Hesselm.) Rønning and ssp. pulvinata (G. Andersson & Hesselm.) Rønning, but no genetic support has been found for such a division (Brysting et al. 1996). However, there may be a racial differentiation between tetraploid (2n = 52) Beringian and North American plants (ssp. smalliana (Engl. & Irmsch.) Hultén or ssp. glandulisepala Hultén) and diploid (2n = 26) European and western Siberian plants (ssp. oppositifolia). The former are characterized by, e.g., glandular sepals, the latter by eglandular sepals. The two are represented by two main lineages in the molecular data analyzed (Abbott et al. 2000; Holderegger & Abbott 2003; Abbott & Comes 2004). Transitions between the two are known from arctic Canada and Greenland (Aiken et al. 2007), recognizable by a few glands on the sepals. Plants with some sepal glands are known from Svalbard as are the tetraploid chromosome number (from two counts). It is therefore feasible that both lineages or subspecies are represented, ssp. smalliana probably only in transitional forms.
Abbott, R.J. & Comes, H.P. 2004. Evolution in the Arctic: a phylogeographic analysis of the circumarctic plant, Saxifraga oppositifolia (Purple saxifrage). – New Phytologist 161: 211–224.
Abbott, R.J., Smith, L.C., Milne, R.I., Crawford, R.M.M., Wolf, K. & Balfour, J. 2000. Molecular analysis of plant migration and refugia in the Arctic. – Science 289: 1343–1346.
Aiken, S.G. (ed.), Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: descriptions, illustrations, identification, and information retrieval. – [CD-ROM version] National Research Council Canada, Ottawa.
Alsos, I.G., Müller, E. & Eidesen, P.B. In prep. Germinability of 87 arctic species stored in Svalbard Global Seed Vault.
Andersson, G. & Hesselman, H. 1901. Bidrag till kännedomen om Spetsbergens och Beeren Eilands kärlväxtflora grundade på iakttagelser under 1889 års svenska polarexpedition. – Bihang till Kungliga Svenska Vetenskaps-Akademiens handlingar 26: 1–88.
Brysting, A.K., Gabrielsen, T.M., Sørlibråten, O., Ytrehorn, O. & Brochmann, C. 1996. The Purple Saxifrage, Saxifraga oppositifolia, in Svalbard: two taxa or one? – Polar Research 15: 93–105.
Hagen, D. 2002. Propagation of native Arctic and alpine species with a restoration potential. – Polar Research 21: 37–47.
Holderegger, R. & Abbott, R.J. 2003. Phylogeography of Arctic–Alpine Saxifraga oppositifolia (Saxifragaceae) and some related taxa based on cpDNA and ITS sequence variation. – American Journal of Botany 90: 931–936.
Hultén, E. 1973. Supplement to Flora of Alaska and neighboring territories. A study in the flora of Alaska and the transberingian connection. – Botaniska Notiser 126: 459–512.
Hultén, E. & Fries, M. 1986. Atlas of North European vascular plants north of the Tropic of Cancer. I–III. – Cramer, Vaduz.
Müller, E., Cooper, E.J. & Alsos, I.G. 2011. Germinability of arctic plants is high in perceived optimal conditions but low in the field. – Botany 89:337-348.
Prop, J., van Erden, M.R. & Drent, R.H. 1984. Reproductive success of Barnacle Goose Branta leucopsis in relation to food exploitation on the breeding grounds, western Spitsbergen. – Norsk Polarinstitutt Skrifter 181: 87–117.
Rønning, O.I. 1996. Svalbards flora. Ed. 3. – Oslo: Norsk Polarinstitutt.
Savile, D.B.O. 1972. Arctic adaptations in plants. – Canada Department of Agriculture Research Branch Monograph 6. 81 pp.
Scientific name, meaning and origin:
Saxifraga: From latin saxum, mountain knoll, and frango, breaking. Plantename by Marcellus Empiricus, app. 410.
Saxifraga oppositifolia ssp. oppositifolia
|English name:||Purple Saxifrage|
|German name:||Roter Steinbrech|
|Saxifraga oppositifolia L. coll.|
|Distribution on Svalbard:|
|Chromosome number (2n):|
|Main mode of pollination:|
|Source: Brochmann, C. & Steen, S.W, 1999 - Sex and genes in the flora of Svalbard|