Saxifraga

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Saxifraga
Saxifraga cochlearis1.jpg
Saxifraga cochlearis
Scientific classification e
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Order: Saxifragales
Family: Saxifragaceae
Genus: Saxifraga
L.
Sections
Synonyms [1]

Boecherarctica Á.Löve
Cascadia A.M.Johnson
Micranthes Haw.
Zahlbrucknera Rchb.

Saxifraga is the largest genus in the family Saxifragaceae, containing about 440 species of holarctic perennial plants, known as saxifrages[2] or rockfoils.[3] The Latin word saxifraga means literally "stone-breaker", from Latin saxum ("rock" or "stone") + frangere ("to break"). It is usually thought to indicate a medicinal use for treatment of urinary calculi (known as kidney stones), rather than breaking rocks apart.[2][4]

The genera Saxifragopsis (strawberry saxifrage), and Saxifragella are sometimes included in Saxifraga.[1] In recent DNA based phylogenetic analyses of the Saxifragaceae, the former sections Micranthes and Merkianae are shown to be more closely related to the Boykinia and Heuchera clades,[5] and the most recent floras separate these groups as the genus Micranthes.[6][7]

Description[edit]

Most saxifrages are smallish plants whose leaves grow close to the ground, often in a rosette. The leaves typically have a more or less incised margin; they may be succulent, needle-like and/or hairy, reducing evaporation.[8]

The inflorescence or single flower clusters rise above the main plant body on naked stalks. The small actinomorphic hermaphrodite flowers have five petals and sepals and are usually white, but red to yellow in some species.[citation needed] As in other primitive eudicots, some of the 5 or 10 stamens may appear petal-like.[citation needed] and it lives tundra ecosystem.

Ecology[edit]

Round-leaved saxifrage (S. rotundifolia), whose sticky leaves seem to catch small invertebrates

Saxifrages are typical inhabitants of Arctic–alpine ecosystems, and are hardly ever found outside the temperate parts of the Northern Hemisphere; most members of this genus are found in subarctic climates. A good number of species grow in glacial habitats, such as S. biflora which can be found some 4,000 metres (13,000 ft) above sea level in the Alps, or the East Greenland saxifrage (S. nathorstii). The genus is also abundant in the Eastern and Western Himalayan alpine shrub and meadows. Though the archetypal saxifrage is a small plant huddling between rocks high up on a mountain, many species do not occur in such a habitat and are larger (though still rather delicate) plants found on wet meadows.

Various Saxifraga species are used as food plants by the caterpillars of some butterflies and moths, such as the Phoebus Apollo (Parnassius phoebus).[9]

Charles Darwin – erroneously believing Saxifraga 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 be protocarnivorous plants, and conducted some experiments whose results supported his observations,[10] but the matter has apparently not been studied since his time.

Cultivation[edit]

Numerous species and cultivars of saxifrage are cultivated as ornamental garden plants, valued particularly as groundcover or as cushion plants in rock gardens and alpine gardens. Many require alkaline or neutral soil to thrive.[8]

S. × urbium (London pride), a hybrid between Pyrenean saxifrage (S. umbrosa) and St. Patrick's cabbage (S. spathularis), is commonly grown as an ornamental plant.[2] Another horticultural hybrid is Robertsoniana saxifrage (S. × geum), derived from kidney saxifrage (S. hirsuta) and Pyrenean saxifrage.[citation needed] Some wild species are also used in gardening. Cambridge University Botanic Garden hosts the United Kingdom's national collection of saxifrages.[2]

Award of Garden Merit[edit]

The following species and cultivars have gained the Royal Horticultural Society's Award of Garden Merit:-[11]

  • ’Angelina Johnson’ (fortunei)[12]
  • ’Blackberry and Apple Pie’ (fortunei)[13]
  • S. callosa (limestone saxifrage)[14]
  • ’Conwy Snow’ (fortunei)[15]
  • ’Coolock Kate’[16]
  • ’Cumulus’[17]
  • S. fortunei[18]
  • ’Gregor Mendel’ (× apiculata)[19]
  • ’Lagraveana’ (paniculata)[20]
  • 'Lutea'[21]
  • 'Minor'[22]
  • ’Moe’ (fortunei)[23]
  • ’Monarch’[24]
  • ’Mount Nachi’ (fortunei)[25]
  • ’Peach Melba’[26]
  • ’Reginald Farrer’ (Silver Farreri Group)[27]
  • ’Rokujo’ (fortunei)[28]
  • 'Rosea'[29]
  • ’Shiranami’ (fortunei)[30]
  • ’Slack’s Ruby Southside’ (Southside Seedling Group)[31]
  • ’Snowflake’ (Silver Farreri Group)[32]
  • ’Southside Star’ (Southside Seedling Group)[33]
  • S. stolonifera (strawberry saxifrage)[34]
  • ’Sue Drew’ (fortunei)[35]
  • Sugar Plum Fairy=‘Toujya’ (fortunei)[36]
  • 'Theoden’[37]
  • 'Tumbling Waters' [38]
  • S. × urbium (London pride)[39]
  • ’Venetia’ (paniculata)[40]
  • ’Whitehill’[41]

Uses[edit]

Purple saxifrage (S. oppositifolia) is a popular floral emblem. It is the territorial flower of Nunavut (Canada) and the county flower of County Londonderry in Northern Ireland.[citation needed] Known as rødsildre ("red saxifrage") in Norway, it also is the county flower of Nordland.[citation needed] It is on the seal of Fitchburg State University, whose motto is "Perseverantia" in reference to the rock-breaking abilities of the plant over time. Tsukuba in Japan has as its city flower hoshizaki-yukinoshita (Katakana: ホシザキユキノシタ), the aptera form of Creeping saxifrage (S. stolonifera).[citation needed] The leaves of the Japanese variety "yukinoshita" (literally "Under the snow") can also been eaten, and is consumed at least within the large southern island of Kyushu. It is prepared by frying the younger succulent leaves in tempura batter.[citation needed]

Selected species[edit]

Formerly placed here[edit]

Plants formerly placed in Saxifraga are mainly but not exclusively Saxifragaceae. They include:[citation needed]

Other "saxifragous" plants[edit]

Several plant genera have names referring to saxifrages, although they might not be close relatives of Saxifraga. They include:[citation needed]

  • Golden-saxifrages, Chrysosplenium
  • Burnet-saxifrages, Pimpinella
  • Pepper-saxifrage, Silaum silaus. The name "silaum" comes from the Latin word sil, which means yellow ochre. This refers to the sulphorous yellow colour of the flowers.[44]

Some plants refer to Saxifraga in their generic names or specific epithets, either because they are also "rock-breaking" or because they resemble members of the saxifrage genus:[citation needed]

References[edit]

  1. ^ a b "Saxifraga L." Germplasm Resources Information Network. United States Department of Agriculture. February 9, 2005. Retrieved January 20, 2009.
  2. ^ a b c d "Saxifraga". National Plant Collections. Cambridge University Botanic Garden. Retrieved October 3, 2011.
  3. ^ Roger Spencer, ed. Horticultural Flora of South-Eastern Australia. UNSW Press, 2002. p. 81. ISBN 9780868401676
  4. ^ D. A. Webb & R. J. Gornall (1989). Saxifrages of Europe. Christopher Helm. p. 19. ISBN 0-7470-3407-9.
  5. ^ Douglas E. Soltis, Robert K. Kuzoff, Elena Conti, Richard Gornall & Keith Ferguson (1996). "matK and rbcL gene sequence data indicate that Saxifraga (Saxifragaceae) is polyphyletic". American Journal of Botany. 83 (3): 371–382. doi:10.2307/2446171.CS1 maint: Multiple names: authors list (link)
  6. ^ Flora of China
  7. ^ Flora of North America
  8. ^ a b RHS A-Z encyclopedia of garden plants. United Kingdom: Dorling Kindersley. 2008. p. 1136. ISBN 1405332964.
  9. ^ Ivo Novák (1980). A Field Guide in Colour to Butterflies and Moths. Octopus Books. ISBN 0-7064-1293-1.
  10. ^ 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.
  11. ^ "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 95. Retrieved 1 November 2018.
  12. ^ "RHS Plantfinder - Saxifraga 'Angelina Johnson'". Retrieved 1 November 2018.
  13. ^ "RHS Plantfinder - Saxifraga 'Blackberry and Apple Pie'". Retrieved 1 November 2018.
  14. ^ "RHS Plant Selector - Saxifraga callosa". Retrieved 2 June 2013.
  15. ^ "RHS Plantfinder - Saxifraga 'Conwy Snow'". Retrieved 1 November 2018.
  16. ^ "RHS Plantfinder - Saxifraga 'Coolock Kate'". Retrieved 1 November 2018.
  17. ^ "RHS Plantfinder - Saxifraga 'Cumulus'". Retrieved 1 November 2018.
  18. ^ "RHS Plant Selector - Saxifraga fortunei". Retrieved 2 June 2013.
  19. ^ "RHS Plantfinder - Saxifraga 'Gregor Mendel' (× fortunei)". Retrieved 1 November 2018.
  20. ^ "RHS Plantfinder - Saxifraga 'Lagraveana'". Retrieved 1 November 2018.
  21. ^ "RHS Plant Selector - Saxifraga 'Lutea'". Retrieved 2 June 2013.
  22. ^ "RHS Plant Selector - Saxifraga 'Minor'". Retrieved 2 June 2013.
  23. ^ "RHS Plantfinder - Saxifraga 'Moe'". Retrieved 1 November 2018.
  24. ^ "RHS Plantfinder - Saxifraga 'Monarch'". Retrieved 1 November 2018.
  25. ^ "RHS Plantfinder - Saxifraga 'Mount Nachi'". Retrieved 1 November 2018.
  26. ^ "RHS Plantfinder - Saxifraga 'Peach Melba'". Retrieved 1 November 2018.
  27. ^ "RHS Plantfinder - Saxifraga (Silver Farreri Group) 'Reginald Farrer'". Retrieved 1 November 2018.
  28. ^ "RHS Plantfinder - Saxifraga 'Rokujo' (fortunei)". Retrieved 1 November 2018.
  29. ^ "RHS Plant Selector - Saxifraga 'Rosea'". Retrieved 2 June 2013.
  30. ^ "RHS Plantfinder - Saxifraga 'Shiranami'". Retrieved 1 November 2018.
  31. ^ "RHS Plantfinder - Saxifraga (Southside Seedling Group) 'Slack's Ruby Southside'". Retrieved 1 November 2018.
  32. ^ "RHS Plantfinder - Saxifraga (Silver Farreri Group) 'Snowflake'". Retrieved 1 November 2018.
  33. ^ "RHS Plantfinder - (Southside seedling Group) 'Southside Star'". Retrieved 1 November 2018.
  34. ^ "RHS Plant Selector - Saxifraga stolonifera". Retrieved 2 June 2013.
  35. ^ "RHS Plantfinder - Saxifraga 'Sue Drew'". Retrieved 1 November 2018.
  36. ^ "RHS Plantfinder - Saxifraga Sugar Plum Fairy='Toujya'". Retrieved 1 November 2018.
  37. ^ "RHS Plant Selector - Saxifraga 'Theoden'". Retrieved 2 June 2013.
  38. ^ "RHS Plant Selector - Saxifraga 'Tumbling Waters'". Retrieved 2 June 2013.
  39. ^ "RHS Plant Selector - Saxifraga × urbium". Retrieved 2 June 2013.
  40. ^ "RHS Plantfinder - Saxifraga 'Venetia' (paniculata)". Retrieved 1 November 2018.
  41. ^ "RHS Plantfinder - Saxifraga 'Whitehill'". Retrieved 1 November 2018.
  42. ^ a b c d e f g h i j k l m n o p q r s t u v w x Umberto Quattrocchi. CRC World Dictionary of Plant Names: Common Names, Scientific Names, Eponyms. Synonyms, and Etymology. CRC Press, 1999. p.2395-2396. ISBN 9780849326738
  43. ^ Knaben, G. (1934). "Saxifraga osloensis n. sp., a tetraploid species of the Tridactylites section". Nytt Magasin for Botanikk: 117–138.
  44. ^ Readers Digest Nature Lover's Library Wild Flowers of Britain, page 192, published 1988

External links[edit]