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Geranium

From Wikipedia, the free encyclopedia
This article is about the botanical genus calledGeranium.For the summer bedding "geranium", seePelargonium.For other uses, seeGeranium (disambiguation).
Not to be confused withgermanium.

Geranium
Geranium dissectum
Scientific classificationEdit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Geraniales
Family: Geraniaceae
Genus: Geranium
L.
Species

See list.

Geraniumis agenusof 422speciesofannual,biennial,andperennialplantsthat are commonly known asgeraniumsorcranesbills.They are found throughout thetemperateregions of the world and the mountains of the tropics, with the greatest diversity in the eastern part of theMediterranean region.[1]

The palmately cleftleavesare broadly circular in form. The flowers have five petals and are coloured white, pink, purple, or blue, often with distinctive veining.[1]Geraniums will grow in any soil as long as it is not waterlogged.[2]Propagationis by semiripe cuttings in summer, by seed, or by division in autumn or spring.[3]

Geraniums are eaten by thelarvaeof someLepidopteraspecies includingbrown-tail,ghost moth,andmouse moth.At least several species ofGeraniumaregynodioecious.[4][5][6]The speciesGeranium viscosissimum(sticky geranium) is considered to beprotocarnivorous.[7]

Name

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Floral diagram of aGeraniumgarden hybrid called ‘Ann Thomson’, showing 5 free sepals, 5 free petals, 10 free fertile stamens, and a superior ovary consisting of 5 merged carpels, with 5 style branches

The genus name is derived fromAncient Greekγέρανος(géranos) 'crane'. The English name 'cranesbill' derives from the resemblance of thefruit capsuleof some of the species to a crane's head and bill. Theovaryportion forms the head and the prolongedstigmacreates the appearance of a beak.[8][9]

Description

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The flowers are typically five-petaled and white to purple. The leaves are palmate divided into narrow, pointed segments.[8]

The fruit capsule consists of five cells joined to a column produced from the centre of the flower. The cells form lobes which eventually separate, each containing one seed.[8]When the fruit is ripe, the beak-like stigma springs open and casts the ovoid, streamlined seeds some distance, dispersing the seeds.[10]

Confusion withPelargonium

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The "bill" and seed dispersal mechanism ofG.pratense

Confusingly, "geranium" is also thecommon nameof members of the genusPelargonium,which are also in thefamilyGeraniaceaeand are widely grown as horticulturalbeddingplants.Linnaeusoriginally included all the species in one genus,Geranium,but they were later separated into two genera byCharles L’Héritierin 1789.[11]Other former members of the genus are now classified inErodium,including the plants known as filarees in North America.[12]

The term "hardy geranium" is often applied to horticulturalGeraniums to distinguish them from thePelargoniums, which are not winter-hardy intemperatehorticulture.[13][14]However, not allGeraniumspecies are winter-hardy (see below).[15]

The shape of the flowers offers one way of distinguishing between the two generaGeraniumandPelargonium.Geraniumflowers have five very similar petals, and are thus radially symmetrical (actinomorphic), whereasPelargonium(and alsoErodium) flowers have two upper petals which are different from the three lower petals, so the flowers have a single plane of symmetry (zygomorphic).[16][17]

Cultivation

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A number of geranium species are cultivated for horticultural use and for pharmaceutical products. Some of the more commonly grown species include:

All the above species are perennials and generally winter-hardy plants, grown for their attractive flowers and foliage. They are long-lived and most have a mounding habit, with palmately lobed foliage. Some species have spreading rhizomes. They are normally grown in part shade to full sun, in well-draining but moisture retentive soils, rich inhumus.[18]Other perennial species grown for their flowers and foliage include:Geranium argenteum,G. eriostemon,G. farreri,G. nodosum,G. procurrens,G. pylzowianum,G. renardii,G. traversii,G. tuberosum,G. versicolor,G. wallichianum,andG. wlassovianum.Some of these are not winter-hardy in cold areas and are grown in specialized gardens like rock gardens.[19]Geranium'Johnson's Blue' is a hybrid betweenG. himalayense(southwestern China), withG. pratense(European meadow cranesbill).[20]

Cultivars

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Close up of a geranium flower (possibly 'Johnson's Blue')

The following hybridcultivarshave gained theRoyal Horticultural Society'sAward of Garden Merit(other cultivars are dealt with under their species name - see above):-[21]

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See also

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References

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  1. ^abAllaby, Michael (26 August 2015).The Dictionary of Science for Gardeners: 6000 Scientific Terms Explored and Explained.Timber Press.ISBN978-1-60469-483-3.Retrieved5 April2024.
  2. ^Tibballs, Geoff (2017-03-09).100 Plants That Won't Die in Your Garden.Little, Brown Book Group.ISBN978-1-4721-3800-2.
  3. ^Brickell, Christopher (2011-08-15).American Horticultural Society Encyclopedia of Plants and Flowers.Penguin.ISBN978-0-7566-7508-0.
  4. ^Hessing, M.B. 1989.Variation in self-fertility and floral characters ofGeranium caespitosum(Geraniaceae) along an elevational gradient.Plant Systematics and Evolution 166:225-241.
  5. ^Van Etten and Chang 2014.Frequency-dependent pollinator discrimination acts against female plants in the gynodioeciousGeranium maculatumAnnals of Botany 114:1769–1778
  6. ^Elzinga, Jelmer A.; Varga, Sandra (2017)."Prolonged stigma and flower lifespan in females of the gynodioecious plant Geranium sylvaticum"(PDF).Flora.226:72–81.Bibcode:2017FMDFE.226...72E.doi:10.1016/j.flora.2016.11.007.S2CID85558947.
  7. ^Spomer, George G. (1999)."Evidence of Protocarnivorous Capabilities in Geranium viscosissimum and Potentilla arguta and Other Sticky Plants".International Journal of Plant Sciences.160(1): 98–101.doi:10.1086/314109.ISSN1058-5893.
  8. ^abcTaylor, Ronald J. (1994) [1992].Sagebrush Country: A Wildflower Sanctuary(rev. ed.). Missoula, MT: Mountain Press Pub. Co. p. 62.ISBN0-87842-280-3.OCLC25708726.
  9. ^"Geranium homeanum".Australian Plants Society.17 January 2024.Retrieved5 April2024.
  10. ^Stamp, Nancy E.; Lucas, Jeffrey R. (1983)."Ecological Correlates of Explosive Seed Dispersal".Oecologia.59(2/3): 272–278.Bibcode:1983Oecol..59..272S.doi:10.1007/BF00378848.ISSN0029-8549.JSTOR4217097.PMID28310244.
  11. ^Lis-Balchin, Maria (2002-10-03).Geranium and Pelargonium: History of Nomenclature, Usage and Cultivation.CRC Press.ISBN978-0-203-21653-8.
  12. ^Armitage, Allan M. (2008-05-01).Herbaceous Perennial Plants: A Treatise on their Identification, Culture, and Garden Attributes.Quarto Publishing Group USA.ISBN978-1-61058-380-0.
  13. ^Parer, Robin (20 April 2016).The Plant Lover's Guide to Hardy Geraniums.Timber Press.ISBN978-1-60469-418-5.
  14. ^"Geranium or Pelargonium? Let's Stop the Confusion".Laidback Gardener.Retrieved2024-04-05.
  15. ^"Geranium Climate: Sun and Temperature".geraniumpage.com.
  16. ^Chris (2015-11-28)."Pelargonium incarnatum - Is it a Geranium? No it's a Pelargonium".Phillipskop Mountain Reserve.Retrieved2024-04-05.
  17. ^"Tom Karwin, On Gardening | Visiting the Geranium family".Santa Cruz Sentinel.2022-11-24.Retrieved2024-04-05.
  18. ^Phillips, Ellen; Colston Burrell, C. (1993),Rodale's illustrated encyclopedia of perennials,Emmaus, Pa.: Rodale Press, pp. 373–76,ISBN978-0-87596-570-3
  19. ^Jelitto, Leo; Schacht, Wilhelm; Epp, Michael E.; Baumgardt (ed. and transl.), John Philip (1990),Hardy herbaceous perennials,vol. 1, Portland, OR: Timber Press, pp. 260–64,ISBN978-0-88192-159-5
  20. ^"Paghat's Garden".Paghat.com.Retrieved2013-09-17.
  21. ^"AGM Plants - Ornamental"(PDF).Royal Horticultural Society. July 2017. p. 39.Retrieved27 February2018.
  22. ^"RHS Plant Selector Geranium 'Ann Folkard' AGM / RHS Gardening".Apps.rhs.org.uk.Retrieved5 April2020.
  23. ^"RHS Plant Selector Geranium × oxonianum 'A.T. Johnson' AGM / RHS Gardening".Apps.rhs.org.uk.Retrieved5 April2020.
  24. ^"Geranium(Cinereum Group) 'Ballerina'".RHS.Retrieved11 July2020.
  25. ^"RHS Plantfinder -Geranium'Blue Cloud'".Retrieved1 March2018.
  26. ^"GeraniumBlue Sunrise='Blogold' (PBR) ".RHS.Retrieved11 July2020.
  27. ^"Geranium'Brookside'".RHS.Retrieved11 July2020.
  28. ^"RHS Plantfinder -Geranium'Danny Boy'".Retrieved2 March2018.
  29. ^"RHS Plant Selector Geranium 'Dilys' AGM / RHS Gardening".Apps.rhs.org.uk.Retrieved2013-09-17.
  30. ^"RHS Plantfinder -G.×lindavicum'Gypsy'".Retrieved1 March2018.
  31. ^"Geranium'Ivan'".RHS.Retrieved11 July2020.
  32. ^"RHS Plant Selector Geranium 'Mavis Simpson' AGM / RHS Gardening".Apps.rhs.org.uk.Retrieved2013-09-17.
  33. ^"Geranium'Nimbus'".RHS.Retrieved11 July2020.
  34. ^"RHS Plant Selector Geranium 'Orion' AGM / RHS Gardening".Apps.rhs.org.uk.Retrieved2013-09-17.
  35. ^"RHS Plantfinder -GeraniumPattricia = 'Brempat'".Retrieved2 March2018.
  36. ^"GeraniumRothbury Gem = 'Gerfos'".RHS.Retrieved14 July2020.
  37. ^"RHS Plant Selector Geranium ROZANNE= 'Gerwat' PBR AGM / RHS Gardening".Apps.rhs.org.uk.Retrieved5 April2020.
  38. ^"RHS Plantfinder -Geranium×riversleainum'Russell Prichard'".Retrieved2 March2018.
  39. ^"Geranium'Sirak'".RHS.Retrieved14 July2020.
  40. ^"Geranium×oxonianum'Wageningen'".RHS.Retrieved11 July2020.
  41. ^"RHS Plant Selector Results / RHS Gardening".Apps.rhs.org.uk.Retrieved5 April2020.

Bibliography

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