Saxifraga is the largestgenus in the familySaxifragaceae, containing about 473species ofholarcticperennial plants, known assaxifrages[1][2] orrockfoils.[3] The Latin wordsaxifraga means literally "stone-breaker", fromLatinsaxum ("rock" or "stone") +frangere ("to break"). It is usually thought to indicate a medicinal use for treatment ofurinary calculi (known as kidney or bladder stones), rather than breaking rocks apart.[2][4]
Theinflorescence or single flower clusters rise above the main plant body on naked stalks. The smallactinomorphichermaphrodite flowers have fivepetals andsepals and are usually white, but red to yellow in some species.Stamens, usually ten, rarely eight, insert at the junction of the floral tube and ovary wall, with filaments subulate or clavate. As in other primitiveeudicots, some of the five or tenstamens may appear petal-like.[citation needed] It lives in tundral ecosystems.[5][8][6]
A genus of about 473 species.[1] The formermonotypic genusSaxifragella has been submersed within Saxifraga, the largest genus inSaxifragaceae, asSaxifraga bicuspidata.[9][5] Also, the genusSaxifragopsis (strawberry saxifrage) was previously included inSaxifraga.[10]
Based on morphological criteria, up to 15 sections were recognised.[11] Subsequentmolecular phylogenetic studies reduced this to 13 sections with 9 subsections. The former sectionsMicranthes andMerkianae are more closely related to theBoykinia andHeucheraclades.[12] Modernfloras separate these groups as the genusMicranthes.[13][6]
Pepper-saxifrage,Silaum silaus. The name "silaum" comes from the Latin word sil, which means yellow ochre. This refers to the sulphurous yellow colour of the flowers.[17]
Some plants refer toSaxifraga in their generic names orspecific epithets, either because they are also "rock-breaking" or because they resemble members of the saxifrage genus:[citation needed]
Saxifrages are typical inhabitants ofArctic–alpineecosystems, and are hardly ever found outside thetemperate parts of the Northern Hemisphere; most members of this genus are found insubarctic climates. A good number of species grow inglacial habitats, such asS. biflora which can be found some 4,000 m (13,000 ft) above sea level in the Alps, or the East Greenland saxifrage (S. nathorstii). The genus is also abundant in theEastern andWestern Himalayan alpine shrub and meadows. Though the archetypal saxifrage is a small planthuddling between rocks high up on a mountain, many species do not occur in such ahabitat and are larger (though still rather delicate) plants found on wetmeadows.
Charles Darwin – erroneously believingSaxifraga to be allied to the sundew family (Droseraceae) – suspected the sticky-leaved round-leaved saxifrage (S. rotundifolia), rue-leaved saxifrage (S. tridactylites) and Pyrenean saxifrage (S. umbrosa) to beprotocarnivorous plants, and conducted some experiments whose results supported his observations,[19] but the matter has apparently not been studied since his time.
Numerous species and cultivars of saxifrage are cultivated as ornamental garden plants, valued particularly asgroundcover or ascushion plants inrock gardens andalpine gardens. Many require alkaline or neutral soil to thrive.[7]
The leaves of some saxifrage species, such as creeping saxifrage (S. stolonifera) andS. pensylvanica,[51] are edible. The former is a food in Korea[52] and Japan.[citation needed] The flowers of purple saxifrage (S. oppositifolia) are eaten inNunavut, Canada and the leaves and stems brewed as a tea.[53]
Species are also used in traditional medicine, such as creeping saxifrage in East Asia[54] and round-leaved saxifrage (S. rotundifolia) in Europe.[55]
Two species—purple saxifrage and creeping saxifrage—are popularfloral emblems. They are official flowers for:
^abcdefghijklmnopqrstuvwxUmberto Quattrocchi.CRC World Dictionary of Plant Names: Common Names, Scientific Names, Eponyms. Synonyms, and Etymology. CRC Press, 1999. p.2395-2396.ISBN9780849326738
^Knaben, G. (1934). "Saxifraga osloensis n. sp., a tetraploid species of theTridactylites section".Nytt Magasin for Botanikk:117–138.
^Reader's Digest Nature Lover's Library Wild Flowers of Britain, page 192, published 1988
^Charles Darwin (1875). "Drosophyllum – Roridula – Byblis – glandular hairs of other plants – concluding remarks on the Droseraceae".Insectivorous Plants (1st ed.). London: J. Murray. pp. 332–367.
^"AGM Plants - Ornamental"(PDF). Royal Horticultural Society. July 2017. p. 95. Retrieved1 November 2018.
^Niering, William A.; Olmstead, Nancy C. (1985) [1979].The Audubon Society Field Guide to North American Wildflowers, Eastern Region. Knopf. p. 780.ISBN0-394-50432-1.
^Ji-xian Guo, Ki Sung Chung, Paul Pui-hay But, Takeatsu Kimura (1996).International Collation Of Traditional And Folk Medicine, Vol 2: Northeast Asia Part 2. World Scientific Publishing Company. p. 65.{{cite book}}: CS1 maint: multiple names: authors list (link)
^Pieroni, Andrea; Quave, Cassandra L., eds. (2014).Ethnobotany and Biocultural Diversities in the Balkans. New York: Springer.
