Pelargonium

{{Short description|Genus of plants}} {{Automatic taxobox |image = Pelargonium cucullatum Contour Path Rhodes Mem.JPG |image_caption = ''Pelargonium cucullatum'' |taxon = Pelargonium |authority = L'Hér.<ref>{{cite book |author=William Aiton |year=1789 |title=Hortus Kewensis |publisher=Nicol |location=London |volume=ii |page=417 |url=https://www.biodiversitylibrary.org/bibliography/4504#/summary}}</ref>{{efn|The generic description of ''Pelargonium'' in ''Hortus Kewensis'' was copied from L’Heritier’s unpublished manuscript titled ''Compendium Generalogium''{{sfn|van der Walt|1979}}}} |type_species=''Pelargonium hirsutum'' (Burm. f.) Sol. ex Aiton ''Pelargonium cucullatum''{{efn|It has been stated that the choice of ''P. hirsutum'' was made arbitrarily,{{sfn|van der Walt|Vorster|1981}} and that ''Pelargonium cucullatum'' (L.) Aiton, designated by van der Walt{{sfn|van der Walt|1979}} should be the lectotype species. Furthermore, ''P. hirsutum'' is not currently recognised as an accepted name.}} (L.) Aiton |diversity_link = List of Pelargonium species |diversity = Around 280 species{{r|powo}} |subdivision_ranks = Subgenera |subdivision = *''Magnipetala'' *''Parvulipetala'' *''Paucisignata'' *''Pelargonium'' }}

'''''Pelargonium''''' ({{IPAc-en|ˌ|p|ɛ|l|ɑr|ˈ|ɡ|oʊ|n|i|.|ə|m}})<ref>{{cite book |title=Sunset Western Garden Book |year=1995 |pages=606–07}}</ref> is a genus of flowering plants commonly called '''geraniums''', '''pelargoniums''', or '''storksbills'''. It includes about 280 species of perennials, succulents, and shrubs.{{r|powo}} Taxonomist Carl Linnaeus originally included all the species of ''Pelargonium'' and ''Geranium'' under the latter name. In 1789, Charles Louis L'Héritier de Brutelle separated them into two genera.

While ''Geranium'' species are mostly temperate herbaceous plants, dying down in winter, ''Pelargonium'' species are evergreen perennials indigenous to warm temperate and tropical regions of the world, with many species in southern Africa. They are drought and heat tolerant but can tolerate only minor frosts. Some species are extremely popular garden plants, grown as houseplants and bedding plants in temperate regions. They have a long flowering period, with flowers mostly in red, orange, or white, but intensive breeding has produced a huge array of cultivars with great variety in size, flower colour, leaf form and aromatic foliage.

== Description == thumb|''Pelargonium sp.'', probably a hybrid thumb|Pelargonium flower

''Pelargonium'' occurs in a large number of growth forms, including herbaceous annuals, shrubs, subshrubs, stem succulents and geophytes.{{sfn|Roschenbleck et al|2014}} The erect stems bear five-petaled flowers in umbel-like clusters, which are occasionally branched. Because not all flowers appear simultaneously, but open from the centre outwards, this is a form of inflorescence is referred to as pseudoumbels.

The flower has a single symmetry plane (zygomorphic), which distinguishes it from the ''Geranium'' flower, which has radial symmetry (actinomorphic). Thus the lower three (anterior) petals are differentiated from the upper two (posterior) petals. The posterior sepal is fused with the pedicel to form a hypanthium (nectary tube). The nectary tube varies from only a few millimeters, up to several centimeters, and is an important floral characteristic in morphological classification. Stamens vary from 2 to 7, and their number, position relative to staminodes, and curvature are used to identify individual species. There are five stigmata in the style.<ref name=PPage/> For the considerable diversity in flower morphology, see figure 1 of Röschenbleck ''et al.'' (2014).{{sfn|Roschenbleck et al|2014}}

Leaves are usually alternate, and palmately lobed or pinnate, often on long stalks, and sometimes with light or dark patterns. The leaves of ''Pelargonium peltatum'' (Ivy-leaved Geranium), have a thick cuticle better adapting them for drought tolerance.<ref>{{cite book|last=Appell|first=Scott D.|title=The Potted Garden: New plants and New approaches for container gardens.|year=2001|isbn=978-1889538228|url=https://books.google.com/books?id=FhGxmyG5HLMC|page={{page needed|date=March 2014}}|publisher=Brooklyn Botanic Garden }}</ref>

== Taxonomy == [[File:Dillenius Pellargonium.jpg|thumb|upright|Dillenius' introduction of the term 'Pelargonium' in ''Hortus Elthamensis'' 1732]] [[File:P inquinans Dillenius.jpg|thumb|upright|''Pelargonium inquinans'', (''Geranium Afric. arborescens''), ''Hortus Elthamensis'']] ''Pelargonium'' is the second largest genus (after ''Geranium'') within the family Geraniaceae, within which it is sister to the remaining genera of the family in its strict sense,<ref name=Price/> ''Erodium'', ''Geranium'', and ''Monsonia'' including ''Sarcocaulon''. The Geraniaceae have a number of genetic features unique amongst angiosperms, including highly rearranged plastid genomes differing in gene content, order and expansion of the inverted repeat.{{sfn|Roschenbleck et al|2014}}

===Genus history=== The name ''Pelargonium'' was first proposed by Dillenius in 1732,{{sfn|Dillenius|1732|loc=[http://bibdigital.rjb.csic.es/ing/Libro.php?Libro=1386&Pagina=280 De Geraniorum Differentiis p. 149]}} who described and illustrated seven species of geraniums from South Africa that are now classified as ''Pelargonium''.<ref name=CCGS1>{{cite web |last=Handlos |first=Wayne |date=2013 |url=http://www.geraniumsonline.com/18thcentury.htm |title=18th Century: Important People, Dates and Publications in the History of '''''Pelargonium''''' |website=Geraniums Online |publisher=Central Coast Geranium Society |access-date=3 August 2017}}</ref>{{sfn|Lis-Balchin|2002|loc=[https://books.google.com/books?id=-bR8GxQ6BU0C&pg=PA52 Diana Miller. The taxonomy of ''Pelargonium'' species and cultivars: Classification history p. 52]}} Dillenius, who referred to these seven species with apparent unique characteristics as ''Geranium Africanum'' (African Geranium){{sfn|Dillenius|1732|loc=[http://bibdigital.rjb.csic.es/ing/Libro.php?Libro=1386&Pagina=284 Geranium Africanum p. 151]}} suggested "''Possent ergo ii, quibus novi generis cupido est, ea, quorum flores inaequales vel et irrregulares sunt, Pelargonia vocare''" (Those who wish a new genus can therefore call those, whose flowers are unequal or irregular, ‘Pelargonia’).{{sfn|Boddy|2013|loc=[https://books.google.com/books?id=24eoWcnoyfcC&pg=PR2 Introduction p. 11]}} The name was then formally introduced by Johannes Burman in 1738. However Carl Linnaeus who first formally described these plants in 1753 did not recognise ''Pelargonium'' and grouped together in the same genus (''Geranium'') the three similar genera ''Erodium'', ''Geranium'', and ''Pelargonium''.{{sfn|Linnaeus|1753|loc=[https://www.biodiversitylibrary.org/item/13830#page/118/mode/1up Geranium p. 676]}} Linnaeus' reputation prevented further differentiation for forty years.{{sfn|Lis-Balchin|2002|loc=[https://books.google.com/books?id=-bR8GxQ6BU0C&pg=PA52 Diana Miller. The taxonomy of ''Pelargonium'' species and cultivars: Classification history p. 52]}} The eventual distinction between them was made by Charles L’Héritier based on the number of stamens or anthers, seven in the case of ''Pelargonium''. In 1774, ''P. cordatum'', ''P. crispum'', ''P. quercifolium'' and ''P. radula'' were introduced, followed by ''P. capitatum'' in 1790.{{sfn|Taylor|2014|loc=[https://books.google.com/books?id=RWuZBgAAQBAJ&pg=PT207 Pelargonium]}}<ref name=CCGS1/>

=== Circumscription === ''Pelargonium'' is distinguished from the other genera in the family Geraniaceae by the presence of a hypanthium, which consists of an adnate nectar spur with one nectary, as well as a generally zygomorphic floral symmetry.{{sfn|Roschenbleck et al|2014}}

=== Subdivision === De Candolle first proposed dividing the genus into 12 sections in 1824, based on the diversity of growth forms.<ref>{{cite book|author=A. P. de Candolle|year=1824–1873|title=Prodromus systematis naturalis regni vegetabilis sive enumeratio contracta ordinum, generum specierumque plantarum huc usque cognitarum, juxta methodi naturalis normas digesta|chapter-url=https://www.biodiversitylibrary.org/item/7150#page/656/mode/1up|chapter=Geraniaceae: Pelargonium|volume=I|page=649|publisher=Sumptibus Sociorum Treuttel et Würtz|display-authors=etal|author-link=A. P. de Candolle}} (also available online at [http://gallica.bnf.fr/ Gallica])</ref> Traditionally the large number of ''Pelargonium'' species have been treated as sixteen sections,<ref name=PPage/><ref>{{cite web |last=Handlos |first=Wayne |date=2010 |url=http://www.geraniumsonline.com/pelsections.htm |title=The Sections of Pelargonium |website=Geraniums Online |publisher=Central Coast Geranium Society |access-date=3 August 2017}}</ref> based on the classification of Knuth (1912) who described 15 sections,<ref>{{cite book |last1=Knuth |first1=R |title=Das Pflanzenreich: regni vegetablilis conspectus|publisher=Engelmann|location=Leipzig|chapter-url=https://www.biodiversitylibrary.org/item/68282#page/322/mode/1up|editor=Adolf Engler|volume=129: Geraniaceae|chapter=5: Pelargonium L'Hér.|page=316|access-date=16 August 2014|year=1912|language=de}}</ref> as modified by van der Walt ''et al''. (1977–1997) who added ''Chorisma'', ''Reniformia'' and ''Subsucculentia''.

These are as follows; * section ''Campylia'' (Lindley ex Sweet) de Candolle * section ''Chorisma'' (Lindley ex Sweet) de Candolle * section ''Ciconium'' (Sweet) Harvey * section ''Cortusina'' (DC.) Harvey * section ''Glaucophyllum'' Harvey * section ''Hoarea'' (Sweet) de Candolle * section ''Isopetalum'' (Sweet) de Candolle * section ''Jenkinsonia'' (Sweet) de Candolle * section ''Ligularia'' (Sweet) Harvey * section ''Myrrhidium'' de Candolle * section ''Otidia'' (Lindley ex Sweet) de Candolle * section ''Pelargonium'' (Sweet) Harvey * section ''Peristera'' de Candolle * section ''Polyactium'' de Candolle * section ''Reniformia'' (Knuth) Dreyer * section ''Subsucculentia'' J.J.A. van der Walt

=== Phylogenetic analyses === All subdivision classifications had depended primarily on morphological differences till the era of phylogenetic analyses (Price and Palmer 1993).<ref name=Price>[https://www.jstor.org/discover/10.2307/2399852?uid=3739416&uid=2&uid=3737720&uid=4&sid=21104578826543 Robert A. Price and Jeffrey D. Palmer. Phylogenetic Relationships of the Geraniaceae and Geraniales from rbcL Sequence Comparisons. Annals of the Missouri Botanical Garden Vol. 80, No. 3 (1993), pp. 661–671]</ref> However phylogenetic analysis shows only three distinct clades, labelled A, B and C.<ref name=Weng/> In this analysis not all sections were monophyletic, although some were strongly supported including ''Chorisma'', ''Myrrhidium'' and ''Jenkinsonia'', while other sections were more paraphyletic. This in turn has led to a proposal, informal at this stage, of a reformulation of the infrageneric subdivision of ''Pelargonium''.

In the proposed scheme of Weng ''et al''. there would be two subgenera, based on clades A+B, and C respectively and seven sections based on subclades. Subsequent analysis with an expanded taxa set confirmed this infrageneric subdivision into two groups which also correspond to chromosome length (<1.5 μ, 1.5-3.0μ),{{sfn|Roschenbleck et al|2014}} but also two subclades within each major clade, suggesting the presence of four subgenera, these correspond to clades A, B, C1 and C2 of the earlier analysis, A being by far the largest clade with 141 taxa. As before the internal structure of the clades supported monophyly of some sections (''Myrrhidium'', ''Chorisma'', ''Reniformia'', ''Pelargonium'', ''Ligularia'' and ''Hoarea'') but paraphyly in others (''Jenkinsonia'', ''Ciconium'', ''Peristera''). A distinct clade could be identified within the paraphyletic ''Polyactium'', designated section ''Magnistipulacea''. As a result, ''Polyactium'' has been split up to provide this new section, which in itself contains two subsections, ''Magnistipulacea'' and ''Schizopetala'', following Knuth's original treatment of ''Polyactium'' as having four subsections.{{sfn|Roschenbleck et al|2014}} [[File:Pelargonium tetragonum.jpg|thumb|upright|Subgenus ''Magnipetala'' section ''Chorisma'': ''P. tetragonum'']] [[File:Pelargonium cotyledonis03.jpg|thumb|upright|Subgenus ''Parvulipetala'' section ''Isopetalum'': ''P. cotyledonis'']] [[File:Pelargonium acetosum (9344387742).jpg|thumb|upright|Subgenus ''Paucisignata'' section ''Ciconium'': ''P. acetosum'']] [[File:Pelargonium tricolor hh.jpg|thumb|upright|Subgenus ''Pelargonium'' section ''Campylia'': ''P. tricolor'']] [[Image:Pelargonium crithmifolium3.jpg|thumb|upright|Subgenus ''Pelargonium'' section ''Otidia'': ''P. crithmifolium'']]

Thus Röschenbleck ''et al.'' (2014) provide a complete revision of the subgeneric classification of ''Pelargonium'' based on four subgenera corresponding to their major clades (A, B, C1, C2); * subgenus ''Magnipetala'' Roeschenbl. & F. Albers Type: ''Pelargonium praemorsum'' (Andrews) F Dietrich * subgenus ''Parvulipetala'' Roeschenbl. & F. Albers Type: ''Pelargonium hypoleucum'' Turczaninow * subgenus ''Paucisignata'' Roeschenbl. & F. Albers Type: ''Pelargonium zonale'' (L.) L'Hér. in Aiton * subgenus ''Pelargonium'' L'Hér. Type: ''Pelargonium cucullatum'' (L.) Aiton{{sfn|Roschenbleck et al|2014}}

Sixteen sections were then assigned to the new subgenera as follows, although many species remained only assigned to subgenera at this stage

* subgenus ''Magnipetala'' 3 sections ** section ''Chorisma'' (Lindley ex Sweet) de Candolle – 4 species ** section ''Jenkinsonia'' (Sweet) de Candolle – 11 species ** section ''Myrrhidium'' de Candolle – 8 species * subgenus ''Parvulipetala'' 3 sections ** section ''Isopetalum'' (Sweet) de Candolle – 1 species (''Pelargonium cotyledonis'' (L.) L'Hér.) ** section ''Peristera'' de Candolle – 30 species ** section ''Reniformia'' (Knuth) Dreyer – 8 species * subgenus ''Paucisignata'' 2 sections ** section ''Ciconium'' (Sweet) Harvey – 16 species ** section ''Subsucculentia'' J.J.A. van der Walt – 3 species * subgenus ''Pelargonium'' 8 sections ** section ''Campylia'' (Lindley ex Sweet) de Candolle – 9 species ** section ''Cortusina'' (DC.) Harvey – 7 species ** section ''Hoarea'' (Sweet) de Candolle – 72 species ** section ''Ligularia'' (Sweet) Harvey – 10 species ** section ''Magnistipulacea'' Roeschenbl. & F. Albers Type: ''Pelargonium schlecteri'' Knuth – 2 subsections *** subsection ''Magnistipulacea'' Roeschenbl. & F. Albers Type: ''Pelargonium schlecteri'' Knuth – 2 species (''P. schlecteri'' & ''P. luridum'') *** subsection ''Schizopetala'' (Knuth) Roeschenbl. & F. Albers Type: ''Pelargonium afrum'' (Eckl. & Zeyh.) Steudel – 3 species (''P. afrum'', ''P. bowkeri'', ''P. schizopetalum'') ** section ''Otidia'' (Lindley ex Sweet) de Candolle – 14 species ** section ''Pelargonium'' L'Hér. – 34 species ** section ''Polyactium'' de Candolle – 2 subsections *** subsection ''Caulescentia'' Knuth – 1 species (''Pelargonium gibbosum'') *** subsection ''Polyactium'' de Candolle – 7 species

=== Subgenera === '''Subgenus ''Magnipetala''''': Corresponds to clade C1, with 24 species. Perennial to short lived, spreading subshrubs, rarely herbaceous annuals. Petals five, but may be four, colour mainly white. Mainly winter rainfall region of South Africa, spreading into summer rainfall region. One species in northern Namibia and Botswana. Two species in East Africa and Ethiopia. Chromosomes x=11 and 9.

'''Subgenus ''Parvulipetala''''': Corresponds to clade B, with 39-42 species. Perennials, partly annuals. Petals five and equal, colour white or pink to deep purplish red. Mainly South Africa, but also other southern hemisphere except South America. a few species in East Africa and Ethiopia. Chromosomes x=7-19.

'''Subgenus ''Paucisignata''''': Corresponds to clade C2, with 25-27 species. Erect sometimes trailing shrubs or subshrubs, rarely geophytes or semi-geophytes. Petals five and equal, colour pink to red sometimes white. Summer rainfall region of South Africa, spreading into winter rainfall region and northern Namibia, with a few species in tropical Africa, Ethiopia, Somalia, Madagascar, the Arabian Peninsula and Asia Minor. Chromosomes x=mainly 9 or 10, but from 4–18.

'''Subgenus ''Pelargonium''''': Corresponds to clade A, with 167 species. Frequently xerophytic deciduous perennials with many geophytes and succulent subshrubs, less frequently woody evergreen shrubs or annual herbs. Petals five, colour shades of pink to purple or yellow. Winter rainfall region of South Africa and adjacent Namibia, spreading to summer rainfall area, and two species in tropical Africa. Chromosomes x=11, may be 8–10.{{sfn|Roschenbleck et al|2014}}

===Species=== {{main|List of Pelargonium species}}

''Pelargonium'' has around 280 species.{{r|powo}}<ref name=Weng>{{cite journal|last1=Weng|first1=ML|last2=Ruhlman|first2=TA|last3=Gibby|first3=M|author-link3=Mary Gibby|last4=Jansen|first4=RK|date=Sep 2012|title=Phylogeny, rate variation, and genome size evolution of Pelargonium (Geraniaceae)| journal=Mol Phylogenet Evol|volume=64|issue=3| pages=654–70|doi=10.1016/j.ympev.2012.05.026 |pmid=22677167|bibcode=2012MolPE..64..654W }}</ref> Röschenbleck ''et al'' lists 281 taxa.{{sfn|Roschenbleck et al|2014}} There is considerable confusion as to which ''Pelargonium'' are true species, and which are cultivars or hybrids. The nomenclature has changed considerably since the first plants were introduced to Europe in the 17th century.<ref name="sayre"/>

=== Etymology === thumb|One of hundreds of garden and houseplant cultivars

The name ''Pelargonium'' is derived from the Greek πελαργός, ''pelargós'' (stork), because the seed head looks like a stork's beak. Dillenius originally suggested the name 'stork', because ''Geranium'' was named after a crane — "''a'' πελαργός, ''ciconia, sicuti vocamus Gerania'', γερανός, ''grus''" (from ''pelargos'', stork, as we call the ''Gerania'', ''geranos'', crane).{{sfn|Dillenius|1732|loc=[http://bibdigital.rjb.csic.es/ing/Libro.php?Libro=1386&Pagina=280 De Geraniorum Differentiis]}}{{sfn|Boddy|2013|loc=[https://books.google.com/books?id=24eoWcnoyfcC&pg=PR2 Introduction p. 11]}}

== Distribution and habitat == ''Pelargonium'' is a large genus within the family Geraniaceae, which has a worldwide distribution in temperate to subtropical zones with some 800 mostly herbaceous species.{{sfn|Roschenbleck et al|2014}} ''Pelargonium'' itself is native to southern Africa (including Namibia) and Australia. Southern Africa contains 90% of the genus, with only about 30 species found elsewhere, predominantly the East African rift valley (about 20 species) and southern Australia, including Tasmania.{{sfn|Roschenbleck et al|2014}} The remaining few species are found in southern Madagascar, Yemen, Iraq, Asia Minor, the north of New Zealand and isolated islands in the south Atlantic Ocean (Saint Helena and Tristan da Cunha) and Socotra in the Indian Ocean.{{sfn|Roschenbleck et al|2014}} The centre of diversity is in southwestern South Africa where rainfall is confined to the winter, unlike the rest of the country where rainfall is predominantly in the summer months.{{sfn|Roschenbleck et al|2014}} Most of the ''Pelargonium'' plants cultivated in Europe and North America have their origins in South Africa.<ref name="sayre">{{cite web |last=Sayre |first=James K. |year=2003 |url=http://www.bottlebrushpress.com/scentedgeraniums.html |title=Scented Geraniums or Pelargoniums |publisher=Bottlebrushpress.com |url-status=dead |archive-url=https://web.archive.org/web/20110708085450/http://www.bottlebrushpress.com/scentedgeraniums.html |archive-date=2011-07-08}}</ref>

==Ecology== ''Pelargonium'' species are eaten by the caterpillars of some Lepidoptera species, including the noctuid moth angle shades, ''Phlogophora meticulosa''. The diurnal butterflies ''Cacyreus marshalli'' and ''C. tespis'' (Lycaenidae), native to southern Africa, also feed on ''Geranium'' and ''Pelargonium''.<ref>{{cite journal|title= Butterflies of Kwazulu-Natal|journal= Durban Natural Science Museum Novitates|url= http://www.durban.gov.za/City_Services/ParksRecreation/museums/nsm/publications/Documents/Novitates%2033.pdf|archive-date= 2015-09-19|access-date= 2017-09-26|archive-url= https://web.archive.org/web/20150919152505/http://www.durban.gov.za/City_Services/ParksRecreation/museums/nsm/publications/Documents/Novitates%2033.pdf|url-status= dead}}</ref> ''C. marshallii'' has been introduced to Europe and can develop into a pest on cultivated Pelargoniums. It has naturalised along the Mediterranean, but does not survive the winter in Westen Europe.<ref>{{cite web|website= UK Butterflies|author= Peter Eeles|title= Geranium bronze|url= http://www.ukbutterflies.co.uk/species.php?species=marshalli|access-date= 2017-09-26}}</ref>

The Japanese beetle, an important agricultural insect pest, becomes rapidly paralyzed after consuming flower petals of the garden hybrids known as "zonal geraniums" (''P.'' × ''hortorum''). The phenomenon was first described in 1920, and subsequently confirmed.<ref>Davis, J.J. 1920. The green Japanese beetle. New Jersey Department of Agriculture Circular. 30: 33.</ref><ref>{{cite journal|last1=Ballou|first1=C. H.|year=1929|title=Effects of geranium on the Japanese beetle| journal=Journal of Economic Entomology|volume=22|issue=2| pages=289–293|doi=10.1093/jee/22.2.289}}</ref><ref>{{cite journal|last1=Potter|first1=D. A.|last2=Held|first2=D. W.|year=1999|title=Absence of food-aversion learning by a polyphagous scarab, Popillia japonica, following intoxication by geranium, Pelargonium x hortorum| journal=Entomologia Experimentalis et Applicata|volume=91| pages=83–88|doi=10.1046/j.1570-7458.1999.00468.x|s2cid=85069089}}</ref><ref>{{cite journal|last1=Held|first1=D. W.|last2=Potter|first2=D. A.|year=2003|title=Characterizing toxicity of Pelargonium spp. and two other reputedly toxic plant species to Japanese beetles (Coleoptera: Scarabaeidae)| journal=Environmental Entomology|volume=32|issue=4| pages=873–880|doi=10.1603/0046-225x-32.4.873|doi-access=free}}</ref> Research conducted by Dr. Christopher Ranger with the USDA Agricultural Research Service and other collaborating scientists have demonstrated the excitatory amino acid called quisqualic acid present within the flower petals is responsible for causing paralysis of the Japanese beetle.<ref>[https://agresearchmag.ars.usda.gov/2010/mar/garden Geraniums and Begonias: New Research on Old Garden Favorites] (the March 2010 issue of ''Agricultural Research'' magazine.)</ref><ref>{{cite journal|author=Ranger, C.M.|author2=Winter, R. E.|author3=Singh, A. P.|author4=Reding, M. E.|author5=Frantz, J. M.|author6=Locke, J. C.|author7=Krause, C. R.|title=Rare excitatory amino acid from flowers of zonal geranium responsible for paralyzing the Japanese beetle|journal=Proceedings of the National Academy of Sciences|year=2011|volume=108|issue=4|pages=1217–1221|doi=10.1073/pnas.1013497108|url=http://www.pnas.org/content/early/2010/12/29/1013497108.full.pdf|pmid=21205899|pmc=3029778|bibcode=2011PNAS..108.1217R|doi-access=free}}</ref> Quisqualic acid is thought to mimic L-glutamic acid, which is a neurotransmitter in the insect neuromuscular junction and mammalian central nervous system.<ref>{{cite book|last1=Usherwood|first1=P. N. R.|title=Advances in Insect Physiology Volume 24|year=1994|chapter=Insect glutamate receptors| series=Advances in Insect Biochemistry and Physiology|volume=24| pages=309–341 |doi=10.1016/S0065-2806(08)60086-7|isbn=9780120242245}}</ref>

A study by the Laboratory of Apiculture & Social Insects group at the University of Sussex on the attractiveness of common garden plants to pollinators found that a cultivar of ''Pelargonium'' × ''hortorum'' was unattractive to pollinators in comparison to other selected garden plants such as ''Lavandula'' (lavender) and ''Origanum''.<ref name="FE12178">{{cite journal|title=Quantifying variation among garden plants in attractiveness to bees and other flower-visiting insects|journal=Functional Ecology|year=2013|doi=10.1111/1365-2435.12178|volume=28|issue=2|pages=364–374|last1=Garbuzov|first1=Mihail|last2=Ratnieks|first2=Francis L. W.|s2cid=83908634 }}</ref>

===Pests and diseases=== {{Main|List of geranium diseases|Pelargonium flower break virus|Pelargonium line pattern virus}}

The geranium bronze butterfly is a pest of ''Pelargonium'' species. The larvae of the geranium bronze bore into the stem of the host plant, causing the stem to typically turn black and die soon after. Geranium bronze are currently listed as an A2 quarantine pest by the European and Mediterranean Plant Protection Organization and can cause significant damage to ''Pelargonium'' species.<ref>{{cite journal|last1=Martinou|first1=A.F.|last2=Papachristos|first2=D.|last3=Milonas|first3=P.G.|title=Report of the Geranium Bronze Butter y, Cacyreus marshalli for mainland Greece|journal=Hellenic Plant Protection Journal.|date=2011}}</ref>

==Cultivation== [[File:1 Pelargonium triste - Kenwyn Nature Park - Cape Town a.jpg|thumb|''Pelargonium triste'', the first species of its genus to be cultivated, here shown in its native habitat in Cape Town]]

Various types of ''Pelargonium'' are regular participants in flower shows and competitive events, with numerous societies devoted exclusively to their cultivation. They are easy to propagate vegetatively from cuttings.<ref name=RHSAZ>{{cite book |title=RHS A-Z encyclopedia of garden plants |year=2008 |publisher=Dorling Kindersley |location=United Kingdom |isbn=978-1405332965 |page=1136}}</ref><ref>{{cite web |url=https://www.bbc.co.uk/gardening/basics/techniques/propagation_pelargoniums1.shtml |title=Gardening - Gardening Guides - Techniques - Taking pelargonium cuttings |work=BBC |date=1970-01-01 |access-date=2013-09-12}}</ref><ref name="patentCA 2704584"/> It is recommended that cuttings should have at least two nodes.<ref>{{Cite web |last=Gardner |first=Eva |title=2023 How to Successfully Propagate Geranium in 5 Simple Steps |url=https://www.helpfulhomeadvice.com/green/propagate-geranium-in-5-steps/ |access-date=2023-06-02 |website=www.helpfulhomeadvice.com |date=2 June 2023 |language=en-US |url-status=dead|archive-url=https://web.archive.org/web/20230602030222/http://www.helpfulhomeadvice.com/green/propagate-geranium-in-5-steps/|archive-date=2023-06-02}}</ref> Zonal geraniums grow in U.S. Department of Agriculture hardiness zones 9 through 12. Zonal geraniums are basically tropical perennials. Although they are often grown as annuals, they may overwinter in zones as cool as zone 7.<ref>[https://homeguides.sfgate.com/minimum-temperatures-geranium-plants-66682.html Minimum Temperatures for Geranium Plants]</ref>

===Cultivation history=== The first species of ''Pelargonium'' known to be cultivated was ''P. triste'', a native of South Africa. It was probably brought to the Botanical Garden in Leiden before 1600 on ships which had stopped at the Cape of Good Hope. In 1631, the English gardener John Tradescant the elder bought seeds from Rene Morin in Paris and introduced the plant to England. By 1724, ''P. inquinans'', ''P. odoratissimum'', ''P. peltatum'', ''P. vitifolium'', and ''P. zonale'' had been introduced to Europe.{{sfn|Taylor|2014|loc=[https://books.google.com/books?id=RWuZBgAAQBAJ&pg=PT207 Pelargonium]}}

=== Cultivars === thumb|Zonal pelargonium

There was little attempt at any rational grouping of ''Pelargonium'' cultivars, the growing of which was revived in the mid-twentieth century, and the origins of many if not most were lost in obscurity. In 1916 the American botanist Liberty Hyde Bailey (1858–1954) introduced two new terms for zonal and regal pelargoniums. Those pelargoniums which were largely derived from ''P. zonale'' he referred to as ''P.'' × ''hortorum'' (i.e. from the garden), while those from ''P. cucullatum'' he named ''P.'' × ''domesticum'' (i.e. from the home).{{sfn|Wilkinson|2007|loc=[https://books.google.com/books?id=6787AwAAQBAJ&pg=PT189 p. 189]}}<ref>{{cite web |last=Handlos |first=Wayne |date=2010 |url=http://www.geraniumsonline.com/lhbailey.htm |title=Connections, Legacies, and Contributions:Liberty Hyde Bailey, Jr. |website=Geraniums Online |publisher=Central Coast Geranium Society |access-date=3 August 2017}}</ref> In the late 1950s a list (the Spalding List) was produced in the United States, based on nursery listings and the 1897 list of Henri Dauthenay.{{sfn|Dauthenay|1897}} It described seven groups, listing each cultivar with the list of its originator, and in most cases a date. These were Species, Zonals, Variegated-Leaved, Domesticum (Regals), Ivy-Leaved, Scented-Leaved and Old. In the 1970s the British Pelargonium and Geranium Society produced a checklist and the Australian Geranium Society started to produce a register but it was not completed till its author, Jean Llewellyn's death in 1999. None of these were published. The most complete list in its time was the 2001 compilation by The Geraniaceae Group,{{sfn|Amadio|2015}} which included all cultivars up to 1959.{{sfn|Wilkinson|2007|loc=[https://books.google.com/books?id=6787AwAAQBAJ&pg=PT220 Appendix 2: Horticultural Classification and Glossary]}}

Registration of cultivars is the responsibility of the Pelargonium & Geranium Society (PAGS: formed in 2009 from the British Pelargonium and Geranium Society and the British and European Geranium Society){{sfn|PAGS|2015|loc=[https://thepags.org/about-us/ About us]}} which administers the International Register of Pelargonium Cultivars.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/about-the-international-register-of-pelargonium-cultivars/ International Register of Pelargonium Cultivars]}} PAGS is the International Cultivar Registration Authority (ICRA) of the International Society for Horticultural Science for pelargoniums.{{sfn|ISHS|2015|loc=ICRA: [http://www.ishs.org/sci/icralist/73.htm Pelargonium and Geranium Society]}}

thumb|Contrasting leaves: Ivy-leaved Group (left) and Zonal Group (right)

Cultivated pelargoniums are commonly divided into six groups{{sfn|RHS|2015|loc=[https://www.rhs.org.uk/advice/profile?PID=338 ''Pelargonium'' (geranium)]}} in addition to species pelargoniums and primary hybrids. The following list is ordered by position in the PAGS classification.{{sfn|PAGS|2015|loc=[https://thepags.org Pelargonium Basics]}} Abbreviations indicate Royal Horticultural Society usage.{{sfn|RHS|2015|loc=[http://apps.rhs.org.uk/horticulturaldatabase/genusclass_hd.asp?genus=Pelargonium Horticultural classification for ''Pelargonium'' L'Her. ex Aiton]}}

* A. Zonal (Z) * B. Ivy-leaved (I) * C. Regal (R) * D. Angel (A) * E. Unique (U) * F. Scented-leaved (Sc) * G. Species * H. Primary hybrids

Of these, A, U and Sc groups are sometimes lumped together as Species Derived (Sppd). This term implies that they are closely related to a species from which they were derived, and do not fit into the R, I or Z groups.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}}

In addition to the primary groups, additional descriptors are used. The Royal Horticultural Society has created description codes. These include;{{sfn|RHS|2015|loc=[http://apps.rhs.org.uk/horticulturaldatabase/genusclass_hd.asp?genus=Pelargonium Horticultural classification for ''Pelargonium'' L'Her. ex Aiton]}}

* Cactus (Ca) * Coloured foliage (C) * Decorative (Dec) * Double (d) * Dwarf (Dw) * Dwarf Ivy-leaved (Dwl) * Frutetorum (Fr) * Miniature (Min) * Miniature Ivy-leaved (MinI) * Stellar (St) * Tulip (T) * Variegated (v)

These may then be combined to form the code, ''e.g.'' ''Pelargonium'' 'Chelsea Gem' (Z/d/v), indicating Zonal Double with variegated foliage.<ref>{{cite web |title=''Pelargonium'' 'Chelsea Gem' |url=https://www.rhs.org.uk/Plants/70117/Pelargonium-Chelsea-Gem-(Z-d-v)/Details?|publisher=Royal Horticultural Society}}</ref> Crosses between groups are indicated with an ×, ''e.g.'' ''Pelargonium'' 'Hindoo' (R × U), indicating a Regal × Unique cross.<ref>{{cite web |title=''Pelargonium'' 'Hindoo'|url=https://www.rhs.org.uk/Plants/61250/Pelargonium-Hindoo-(R-×-U)/Details|publisher=Royal Horticultural Society}}</ref>

==== A. Zonal pelargoniums (''Pelargonium'' × ''hortorum'' Bailey) ==== thumb|upright|''Pelargonium'' × ''hortorum'' (Zonal)

These are known as zonal geraniums because many have zones or patterns in the center of the leaves,<ref name="patentCA 2704584"/> this is the contribution of the ''Pelargonium zonale'' parent. Common names include storksbill, fish or horseshoe geraniums.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}} They are also referred to as ''Pelargonium'' × ''hortorum'' Bailey. Zonal pelargoniums are tetraploid, mostly derived from ''P. inquinans'' and ''P. zonale'',<ref>{{PLANTS|id=PEHO2|taxon=Pelargonium ×hortorum|access-date=5 August 2017}}</ref> together with ''P. scandens'' and ''P. frutetorum''.<ref name="patentCA 2704584"/>{{sfn|RHS|2015|loc=[https://www.rhs.org.uk/advice/profile?PID=338 ''Pelargonium'' (geranium)]}}

Zonal pelargoniums are mostly bush-type plants with succulent stems grown for the beauty of their flowers, traditionally red, salmon, violet, white or pink.<ref name="patentCA 2704584"/> The scarlet colouring is attributed to the contribution of ''P. inquinans''.{{sfn|Taylor|2014|loc=[https://books.google.com/books?id=RWuZBgAAQBAJ&pg=PT207 Pelargonium]}} Flowers may be double or single. They are the pelargoniums most often confused with the genus ''Geranium'', particularly in summer bedding arrangements. This incorrect nomenclature is widely used in horticulture, particularly in North America.{{sfn|Taylor|2014|loc=[https://books.google.com/books?id=RWuZBgAAQBAJ&pg=PT207 Pelargonium]}}

Zonals include a variety of plant types along with genetic hybrids such as hybrid ivy-leaved varieties that display little or no ivy leaf characteristics (the Deacons varieties), or the Stellar varieties. Hybrid zonals are crosses between zonals and either a species or species-derived pelargonium.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}} There are hundreds of zonal cultivars available for sale,<ref>[http://www.hutchinsonfarm.ca/Flowers/GeraniumsZonal.html Hutchinson Farm: Zonal Geraniums]</ref> and like other cultivars are sold in series such as 'Rocky Mountain',<ref>[http://www.hutchinsonfarm.ca/Flowers/GeraniumRockies.html Hutchinson Farm: Rocky Mountain Geraniums]</ref> each of which is named after its predominant colour, ''e.g.'' 'Rocky Mountain Orange', 'White', 'Dark Red', ''etc''.<ref>[http://utgardens.tennessee.edu/2008_results.asp?id=209 The University of Tennessee Gardens: Pelargonium x hortorum Rocky Mountain™ 'Dark Red']</ref> thumb|upright|'Rocky Mountain Orange' (Zonal)

*(i) Basic plants – Mature plants with foliage normally exceeding {{convert|18|cm|4=0|abbr=on}} in height above the rim of the pot. For exhibition these should be grown in a pot exceeding {{convert|12|cm|frac=4|abbr=on}} in diameter but not normally exceeding {{convert|165|mm|in|frac=2|abbr=on}}. *(ii) Dwarf plants – Smaller than basic. Mature plants with foliage more than {{convert|12.5|cm|4=0|abbr=on}} above the rim of the pot, but not normally more than {{convert|18|cm|4=0|abbr=on}}. For exhibition should be grown in a pot exceeding {{convert|9|cm|frac=2|abbr=on}} but not exceeding {{convert|12|cm|frac=4|abbr=on}}. They should not exceed 20 cm in height, grown in an 11-cm pot.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}} *(iii) Miniature plants – Slowly growing pelargoniums. Mature plants with foliage normally less than {{convert|12.5|cm|4=0|abbr=on}} above the rim of the pot. For exhibition should be grown in a pot not exceeding {{convert|9|cm|frac=2|abbr=on}}. They should not exceed 12.5 cm in height, grown in a 9-cm pot.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}} *(iv) Micro-miniature plants – Smaller and more slowly growing than miniature pelargoniums. Mature plants with foliage normally less than {{convert|10|cm|4=0|abbr=on}} above the rim of the pot. They should not exceed 7.5 cm in height, grown in a 6-cm pot.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}} Usually no separate classes for these in exhibition and will therefore normally be shown as Miniature Zonals. *(v) Deacon varieties –Genetic hybrid similar to a large Dwarf. For exhibition (when shown in a separate class), usually grown in a pot not exceeding {{convert|12.5|cm|4=0|abbr=on}}, otherwise as for Dwarf Zonals. *(vi) Stellar varieties – A relatively modern genetic hybrid originating from the work done by the Australian hybridiser Ted Both in the late 1950s and 1960s from crosses between Australian species and Zonal types. Easily identifiable by their distinctive half-star-shaped leaves and slim-petalled blooms which create an impression of being star shaped (or five fingered). Single varieties tend to have larger elongated triangular petals whereas doubles tend to have thin feathered petals that are tightly packed together. For exhibition purposes there is a separate class for 'Stellar' varieties, but being Zonals could be shown in an open class for Basic, Dwarf or Miniature Zonals (unless otherwise stated). Also known as "The Five-fingered Geraniums", "Staphysagroides", "Both’s Staphs", "Both’s Hybrid Staphs", "Fingered Flowers" and "Bodey’s Formosum Hybrids".{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}} *(vii) Zonartic hybrids – Zonartic pelargoniums are a group of hybrids bred by Australian horticulturist Cliff Blackman. Hybridisation to establish this group began in 1985 through crosses between zonal pelargoniums (Pelargonium × hortorum) and the wild species Pelargonium articulatum. The name “Zonartic” derives from zonal and articulatum, reflecting this genetic combination. Blackman’s breeding programme produced a distinctive line of pelargoniums noted for their large, luminous flowers and for his effort to develop a true yellow pelargonium. Since then, Zonartic breeding has spread internationally, with active hybridisers in the United Kingdom, Sweden, Russia, and other countries. Breeders often identify their hybrids through a prefix; for example, Blackman used the prefix ‘Lara’ for his cultivars.<ref>{{Cite web |last=Blackman |first=Clifford |title=Pelargonium hybridising : the Lara Originations 1970 to 2012 / Clifford Blackman; editing by Ralf and Patricia (nee Blackman) Harries |url=https://catalogue.nla.gov.au/catalog/7789070 |access-date=7 October 2025 |website=National Library of Australia}}</ref>

Fancy-leaf zonal pelargoniums – besides having green leaves with or without zoning, this group also have variable coloured foliage{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}} that is sometimes used in classifying for exhibition purposes, ''e.g.'' 'Bicolour', 'Tricolour', 'Bronze' or 'Gold'. Other foliage types are: 'Black' or 'Butterfly'. There are an increasing number of these plants with showy blooms;

*(a) Bicolour – includes those with white or cream veined leaves or those with two distinct colours with clearly defined edges, other than the basic zone. *(b) Tricolour – (May be Silver Tricolour (usually called a Silver Leaf) or a Gold Tricolour). **(i) Gold Tricolour – Leaves of many colours including red and gold, but usually with clearly defined edges of golden yellow and having a leaf zone, usually red or bronze, that overlays two or more of the other distinct leaf colours, so that the zone itself appears as two or more distinct colours. **(ii) Silver Tricolour or Silver Leaf – These tend to resemble a normal bi-colour leaf plant with two distinct colours usually of green and pale cream or white; the third colour is usually made up of bronze zoning. When this zoning overlays the green part of the leaf it is deemed to represent a silver colour. *(c) Bronze Leaved – Leaves of Green or Golden/Green with a heavy bronze or chestnut coloured centre zone which is known as a medallion. For exhibition purposes, when exhibited in specific ‘Bronze’ Leaf class – Must have over 50% of leaf surface bronze coloured. The dwarf plant ‘Overchurch’ which has a heavy bronze medallion. *(d) Gold Leaved – Leaves coloured golden/yellow or green/yellow but not showing a tendency to green. For exhibition purposes, when exhibited in specific ‘Gold’ Leaf class – Must have over 50% of leaf surface gold coloured. *(e) Black Leaved – Leaves coloured black, purple-black or with distinct large dark zones or centre markings on green. *(f) Butterfly Leaved – Leaves with a butterfly marking of distinct tone or hue in centre of leaf. This can be encompassed in many of the coloured leaf varieties.

Zonal pelargoniums have many flower types, as follows:{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}}

*(a) Single flowered (S) – each flower pip normally having no more than five petals. This is the standard flower set for all Pelargoniums. *(b) Semi-double flowered (SD) – each flower pip normally having between six and nine petals. *(c) Double flowered (D)– each flower pip composed of more than nine petals (i.e. double the standard flower set) but not ‘hearted’ like the bud of a rose, ''e.g.'' the dwarf ‘Dovepoint’ which has full double blooms. *(d) Rosebud (or noisette) flowered – each bloom fully double and ‘hearted’. The middle petals are so numerous that they remain unopened like the bud of a rose.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}} *(e) Tulip flowered – having semi-double blooms that never fully open. The large cup shaped petals open just sufficiently to resemble a miniature tulip. *(f) Bird's-egg group – having blooms with petals that have spots in a darker shade than the base colour, like many birds eggs.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}} *(g) Speckled flowered group – having petals that are marked with splashes and flecks of another colour, ''e.g.'' ‘Vectis Embers’. *(h) Quilled (or cactus-flowered group, or poinsettia in US) – having petals twisted and furled like a quill.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}}

“Zonquil” pelargoniums result from a cross between Zonal pelargonium cultivars and ''P. quinquelobatum''.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}}

==== B. Ivy-leaved pelargoniums (derived from ''Pelargonium peltatum'') ==== [[File:Geraniaceae.jpg|thumb|upright|''Pelargonium peltatum'' (Ivy-leaved)]]

Also known as "ivy geraniums".{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}} Usually of lax growth (trailing), mainly due to the long thin stems, with thick, waxy ivy-shaped stiff fleshy evergreen leaves developed by the species ''P. peltatum'' to retain moisture during periods of drought. Much used for hanging pots, tubs and basket cultivation. In the UK the bulbous double-headed types are preferred whilst on the European continent the balcon single types for large-scale hanging floral displays are favoured. Ivy-leaved pelargoniums embrace all such growth size types including small-leaved varieties and genetic hybrid crosses, which display little or no zonal characteristics. May have bicolour leaves and may have flowers that are single, double or rosette. Ivy pelargoniums are often sold as series such as 'Great Balls of Fire', in a variety of colours such as 'Great Balls of Fire Burgundy'.

Additional descriptive terms include;{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}}

* Hybrid Ivy — the result of ivy × zonal crosses, but still more closely resemble ivy-leaved pelargoniums. * Fancy leaf — leaves with marked color variation, together with or other than green. * Miniature — miniature leaves and flowers, stems with short nodes, and compact growth. ''e.g.'' 'Sugar Baby'<ref>{{cite web |title=''Pelargonium'' 'Sugar Baby' |url=https://www.rhs.org.uk/Plants/51136/Pelargonium-Sugar-Baby-(DwI)/Details |publisher=Royal Horticultural Society}}</ref> listed as Dwarf Ivy (DwI) by RHS.{{sfn|RHS|2015|loc=[http://apps.rhs.org.uk/horticulturaldatabase/genusclass_hd.asp?genus=Pelargonium Horticultural classification for ''Pelargonium'' L'Her. ex Aiton]}}

==== C. Regal pelargoniums (''Pelargonium'' × ''domesticum'' Bailey) ==== thumb|upright|'Karl Offenstein' (Regal)

These are large bush-type floriferous evergreen pelargoniums. In addition to "Regals" they are also known as “Show Pelargoniums”. In the US they are often known as the "Martha Washington" or "Lady Washington" pelargoniums. They are grown primarily for the beauty and richness of their flower heads, which are large. Most of those cultivars grown currently are the result of hybridization over the last 50 years. They are very short-jointed and compact, which results in their requiring very little work in order to create a floriforous and well-rounded plant.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}}{{sfn|PAGS|2015|loc=[https://thepags.org Pelargonium Basics]}} Flowers are single, rarely double, in mauve, pink, purple or white. They have rounded, sometimes lobed or partially toothed (serrated) leaves, unlike the Zonal groups, without any type of zoning.

Additional descriptive terms include;{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}}

* Fancy leaf – Leaves with marked variations in colour * Decorative pelargoniums (Decoratives) – Descendants of older, less compact, smaller-flowered varieties that are more suited to outdoor conditions. These have smaller flowers than Regal, but are otherwise similar. ''e.g.'' 'Royal Ascot' * Miniature – Flowers and leaves similar to Regal, but miniature in form, with compact growth. Other terms include "Pansy Geraniums" or "Pansy Pelargoniums". ''e.g.'' 'Lara Susan' * Oriental pelargoniums – The result of crosses between Regals and members of the Angel group (see below). Some have bicolour foliage.

==== D. Angel pelargoniums (derived from ''Pelargonium crispum'') ==== thumb|upright|'Angeleyes Randy' (Angel)

Angel pelargoniums are similar to Regal pelargoniums but more closely resemble ''P. crispum'' in leaf shape and growth habit. The majority of Angel cultivars originate from a cross between ''P. crispum'' and a Regal variety in the early part of the 20th century. Angels have grown in popularity in the last 30 years or so due mainly to an explosion of new varieties being released by specialist nurseries resulting from the work done by dedicated amateur hybridisers. These hybrisers have managed to obtain many new flower colour breaks and tighter growth habits resulting in plants suitable for all sorts of situations. Angels basically have the appearance of a small Regal with small serrated leaves and much smaller flowers and are more compact and bushy. The group extends to include similar small-leaved and -flowered types but usually with ''P. crispum'' in their parentage. They are mostly upright bush-type plants but there are some lax varieties that can be used for basket or hanging pot cultivation. Often called "pansy-faced" in the US. Some varieties have bicolour foliage. Other terms include ‘Langley-Smith Hybrids’.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}}

==== E. Unique pelargoniums (derived from ''Pelargonium fulgidum'') ==== thumb|upright|'White Unique' (Unique)

Unique in sense of not fitting into any of the above categories. The parentage of Unique pelargoniums is confused and obscure. One theory being a derivation from ''P. fulgidum'', but a derivation from an older cultivar 'Old Unique', also known as or 'Rollinson’s Crimson', in the mid-19th century is also claimed.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}} Unique pelargoniums resemble upright Scented Leaf pelargoniums in being shrubby and woody evergreens. They have distinctly scented leaves, and small flowers with blotched and feathered petals. They may have bicolour foliage. Some types, popularly known in the hobby as hybrid Uniques, have been crossed with Regal pelargoniums and, as a result of this cross, are much more floriferous.

; Cultivar: * Fiery-flowered Stork's-bill, Scarlet Unique Scented Geranium (''P''. × ''ignescens''){{sfn|Sweet|1822|loc=[https://www.biodiversitylibrary.org/item/182545#page/25/mode/1up ''Pelargonium ignescens'']}} – a ''P. fulgidum'' hybrid<ref>{{cite web |last=Cornett |first=Peggy |date=2013 |url=https://www.monticello.org/site/research-and-collections/pelargonium-fulgidum-hybrid-scarlet-unique-geranium |title=Pelargonium fulgidum hybrid - Scarlet Unique Geranium |website=Monticello.org |publisher=Thomas Jefferson Encyclopedia |access-date=3 August 2017}}</ref>

==== F. Scented-leaved pelargoniums ==== [[Image:Pelargonium graveolens 2.jpg|thumb|upright|''P. graveolens'' (scented leaf)]]

Shrubby evergreen perennials grown chiefly for their fragrance, may be species or cultivars but all must have a clear and distinct scented foliage. Scent is emitted when the leaves are touched or bruised with some scents aromatic, others pungent and in a few cases, quite unpleasant. Several of the scented leaved pelargoniums are grown for the oil geraniol, which is extracted from the leaves and is an essential oil much used commercially in perfumery. The scent of some species growing in their natural habitat, acts as a deterrent to grazing animals who appear to dislike the emitted scent. Conversely, it also attracts other insect life to visit the bloom and pollinate the plant. The scented leaves can be used for potpourri and they also have a use as flavourings in cooking. Occasionally scented types can be found in some of the other groups mentioned; for example, the Angels, having ''P. crispum'' in their genetic makeup, can often have a strong citrus scent. Leaves are lobed, toothed, incised or variegated. Growth habit is very variable, but the flowers are less prominent than other groups, and most closely resemble the species they originated from.{{sfn|PAGS|2015|loc=[http://thepelargoniumregister.com/horticulture-symbols-and-terms/ Horticultural symbols and terms]}}

* Almond - ''Pelargonium quercifolium'' * Apple - ''Pelargonium odoratissimum'' * Apple - ''Pelargonium cordifolium'' * Apple/Mint - ''Pelargonium album'' * Apricot/Lemon - ''Pelargonium scabrum'' * Balsam - ''Pelargonium panduriforme'' * Camphor - ''Pelargonium betulinum'' * Celery - ''Pelargonium ionidiflorum'' * Cinnamon - ''Pelargonium 'Ardwyck Cinnamon''' * Coconut - ''Pelargonium grossalarioides'' (''Pelargonium parriflorum'') * Eau de Cologne - ''Pelargonium 'Brilliantine''' * Eucalyptus - ''Pelargonium 'Secret Love''' * Grapefruit - ''Pelargonium 'Poquita''' * Ginger - ''Pelargonium 'Torrento''' or 'Cola Bottles' which is a variety of ''Pelargonium'' x ''nervosum'' * Hazelnut - ''Pelargonium 'Odorata Hazelnut'' * Lavender - ''Pelargonium 'Lavender Lindy''' * Lemon - ''Pelargonium crispum'' * Lemon - ''Pelargonium citronellum'' (Synonym - ''Pelargonium'' 'Mabel Grey') * Lemon Balm - ''Pelargonium x melissinum'' * Lime - ''Pelargonium x nervosum'' * Myrrh - ''Pelargonium myrrhifolium'' * Nutmeg - ''Pelargonium x fragrans'' * Old Spice - ''Variety of Pelargonium x fragrans'' * Orange - ''Pelargonium x citriodorum'' (Synonym - ''Pelargonium'' 'Prince of Orange') * Peach - ''Pelargonium 'Peaches and Cream''' * Peppermint - ''Pelargonium tomentosum'' * Pine - ''Pelargonium denticulatum'' * Pineapple - ''Pelargonium 'Brilliant''' * Raspberry - ''Pelargonium 'Red Raspberry''' * Rose - ''Pelargonium graveolens'' (Synonym - ''Pelargonium roseum'') * Rose - ''Pelargonium capitatum'' * Rose - ''Pelargonium radens'' * Southernwood - ''Pelargonium abrotanifolium'' * Spicy - ''Pelargonium exstipulatum'' * Strawberry - ''Pelargonium x scarboroviae''

; Cultivars: * 'Attar of Roses' - a cultivar of ''P. capitatum'' * 'Crowfoot Rose' - a cultivar of ''P. radens'' * 'Dr. Livingston' - a cultivar of ''P. radens'' * 'Grey Lady Plymouth' - a cultivar of ''P. graveolens'' * 'Prince Rupert' - a cultivar of ''P. crispum''

==== G. Species pelargoniums ==== The species are the forefathers of all the cultivar groups listed above. In general, the definition of a species is that it breeds true, and is to be found doing this in the "wild". Species pelargoniums have a large diversity of characteristics in habit, shape, size and colour, which probably accounts for them having retained their popularity for more than 300 years.

==== H. Primary hybrids ==== A primary hybrid is recognised as being the resultant plant from a first-time cross between two different known species. Examples are ''P''. × ''ardens'' – from ''P. lobatum'' × ''P. fulgidum'' (1810). ''P''. × ''glauciifolium'' – from ''P. gibbosum'' × ''P. lobatum'' (1822). Primary hybrids are usually, but not always, sterile.

The following is a selection of pelargoniums which have gained the Royal Horticultural Society's Award of Garden Merit: *'Attar of Roses' (rose scented leaves, pink flowers)<ref>{{cite web|title=''Pelargonium'' 'Attar of Roses'|url=https://www.rhs.org.uk/Plants/59357/Pelargonium-Attar-of-Roses-(Sc)/Details|publisher=Royal Horticultural Society | access-date = 25 January 2021}}</ref> *'Citriodorum' (lemon scented leaves, rose pink flowers)<ref>{{cite web|title=''Pelargonium'' 'Citriodorum'|url=https://www.rhs.org.uk/Plants/51572/Pelargonium-Citriodorum-(Sc)/Details|publisher=Royal Horticultural Society | access-date = 16 January 2021}}</ref> *'Dolly Varden' (variegated leaves, scarlet flowers)<ref>{{cite web|title=''Pelargonium'' 'Dolly Varden'|url=https://www.rhs.org.uk/Plants/79978/Pelargonium-Dolly-Varden-(Z-v)/Details|publisher=Royal Horticultural Society | access-date = 16 January 2021}}</ref> *'Frank Headley' (cream vareigated leaves, salmon pink flowers)<ref>{{cite web|title=''Pelargonium'' 'Frank Headley'|url=https://www.rhs.org.uk/Plants/79978/Pelargonium-Dolly-Varden-(Z-v)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Fringed Aztec' (white & purple fringed flowers)<ref>{{cite web|title=''Pelargonium'' 'Fringed Aztec'|url=https://www.rhs.org.uk/Plants/44812/Pelargonium-Fringed-Aztec-(R)/Details|publisher=Royal Horticultural Society|access-date = 16 January 2021}}</ref> *'Gemstone' (scented leaves, pink flowers)<ref>{{cite web|title=''Pelargonium'' 'Gemstone'|url=https://www.rhs.org.uk/Plants/54834/Pelargonium-Gemstone-(Sc)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Grace Thomas' (lemon scented leaves, pale pink flowers)<ref>{{cite web|title=''Pelargonium'' 'Grace Thomas'|url=https://www.rhs.org.uk/Plants/110630/Pelargonium-Grace-Thomas-(Sc)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Joy' (pink & white frilled flowers)<ref>{{cite web|title=''Pelargonium'' 'Joy'|url=https://www.rhs.org.uk/Plants/105735/Pelargonium-Joy-(R)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Lady Plymouth' (''P. graveolens variegata'' – small mauve flowers)<ref>{{cite web|title=''Pelargonium'' 'Lady Plymouth'|url=https://www.rhs.org.uk/Plants/83501/Pelargonium-Lady-Plymouth-(Sc-v)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Lara Candy Dancer' (scented leaves, pale mauve flowers)<ref>{{cite web|title=''Pelargonium'' 'Lara Candy Dancer'|url=https://www.rhs.org.uk/Plants/111945/Pelargonium-Lara-Candy-Dancer-(Sc)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Lara Starshine' (aromatic leaves, lilac flowers)<ref>{{cite web|title=''Pelargonium'' 'Lara Starshine'|url=https://www.rhs.org.uk/Plants/75161/Pelargonium-Lara-Starshine-(Sc)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'L'Élégante' (ivy-leaved, trailing, white and purple flowers)<ref>{{cite web|title=''Pelargonium'' 'L'Élégante'|url=https://www.rhs.org.uk/Plants/77226/Pelargonium-L-elegante-(I-v)/Details|publisher=Royal Horticultural Society|access-date = 16 January 2021}}</ref> *'Mabel Grey' (lemon-scented leaves, mauve flowers)<ref>{{cite web|title=''Pelargonium'' 'Mabel Grey'|url=https://www.rhs.org.uk/Plants/46345/Pelargonium-Mabel-Grey-(Sc)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Mrs Quilter' (bronze leaves, salmon pink flowers)<ref>{{cite web|title=''Pelargonium'' 'Mrs Quilter'|url=https://www.rhs.org.uk/Plants/71148/Pelargonium-Mrs-Quilter-(Z-C)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Radula' (lemon & rose scented leaves, pink & purple flowers)<ref>{{cite web|title=''Pelargonium'' 'Radula'|url=https://www.rhs.org.uk/Plants/119280/Pelargonium-Radula-(Sc)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Royal Oak' (balsam scented leaves, mauve flowers)<ref>{{cite web|title=''Pelargonium'' 'Royal Oak'|url=https://www.rhs.org.uk/Plants/74032/Pelargonium-Royal-Oak-(Sc)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Spanish Angel' (lilac & magenta flowers)<ref>{{cite web|title=''Pelargonium'' 'Spanish Angel'|url=https://www.rhs.org.uk/Plants/85682/Pelargonium-Spanish-Angel-(A)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Sweet Mimosa' (balsam-scented leaves, pale pink flowers)<ref>{{cite web|title=''Pelargonium'' 'Sweet Mimosa'|url=https://www.rhs.org.uk/Plants/83869/Pelargonium-Sweet-Mimosa-(Sc)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Tip Top Duet' (pink & wine-red flowers)<ref>{{cite web|title=''Pelargonium'' 'Tip Top Duet'|url=https://www.rhs.org.uk/Plants/45720/Pelargonium-Tip-Top-Duet-(A)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *'Voodoo' (crimson & black flowers)<ref>{{cite web|title=''Pelargonium'' 'Voodoo'|url=https://www.rhs.org.uk/Plants/59491/Pelargonium-Voodoo-(U)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref> *''P. tomentosum'' (peppermint-scented leaves, small white flowers)<ref>{{cite web|title=''Pelargonium tomentosum''|url=https://www.rhs.org.uk/Plants/46730/Pelargonium-tomentosum-(Sc)/Details|publisher=Royal Horticultural Society| access-date = 16 January 2021}}</ref>

==Uses==

=== Ornamental plants === Pelargoniums rank as one of the highest number of potted flowering plants sold and also in terms of wholesale value.<ref name="patentCA 2704584"/>

=== Scented leaf pelargoniums === Other than being grown for their beauty, species such as ''P. graveolens'' are important in the perfume industry and are cultivated and distilled for their scents. Although scented pelargoniums exist which have smells of citrus, mint, pine, spices or various fruits, the varieties with rose scents are most commercially important.{{citation needed|date=July 2012}} Pelargonium distillates and absolutes, commonly known as "scented geranium oil" are sometimes used to supplement or adulterate expensive rose oils. The oils of the scented pelargoniums contain citronellol, geraniol, eugenol, alpha-pinene and many other compounds. The edible leaves and flowers are also used as a flavouring in desserts, cakes, jellies and teas. Scented-leafed pelargoniums can be used to flavor jellies, cakes, butters, ice cream, iced tea and other dishes, The rose-, lemon- and peppermint-scents are most commonly used. Also used are those with hints of peach, cinnamon and orange. Commonly used lemon-scented culinary species include ''P. crispum'' and ''P. citronellum''. Rose-scenteds include ''P. graveolens'' and members of the ''P. graveolens'' cultivar group. Other species and cultivars with culinary use include the lime-scented ''P.'' ‘Lime’, the lemon balm-scented ''P''. 'Lemon Balm', the strawberry-lemon-scented ''P.'' ‘Lady Scarborough’ and the peppermint-scented ''P. tomentosum''.<ref name=HSA2006>{{cite web|title=Pelargoniums - An Herb Society of America Fact Sheet|url=http://www.herbsociety.org/factsheets/pelargoniums_fact.pdf|publisher=The Herb Society of America|year=2006|access-date=20 December 2012|url-status=dead|archive-url=https://web.archive.org/web/20120227124006/http://www.herbsociety.org/factsheets/pelargoniums_fact.pdf|archive-date=27 February 2012}}</ref> Scented leaf pelargoniums have also been historically used as toilet paper by fishermen in remote places, such as the Minquiers.<ref>{{Cite web |last=Stables |first=Daniel |title=The British islands that disappear every day |url=https://www.bbc.com/travel/article/20220828-the-british-islands-that-disappear-every-day |access-date=2022-08-30 |website=www.bbc.com |date=29 August 2022 |language=en}}</ref>

===Herbal medicine=== In herbal medicine, ''Pelargonium'' has been used for intestinal problems, wounds and respiratory ailments, but ''Pelargonium'' species have also been used for fevers, kidney complaints and other conditions. Geranium (Pelargonium) oil is considered a relaxant in aromatherapy, and in recent years, respiratory/cold remedies made from ''P. sidoides'' and ''P. reniforme'' have been sold in Europe and the US.<ref name=HSA2006 /> ''P. sidoides'' along with ''Echinacea'' is used for bronchitis.<ref>{{cite web|title=Pelargonium sidoides (African geranium)|url=http://www.wholehealthchicago.com/3406/pelargonium-sidoides-african-geranium/|publisher=WholeHealth Chicago|date=2010-02-14}}</ref> ''P. odoratissimum'' is used for its astringent, tonic and antiseptic effects. {{citation needed|date=May 2016}} It is used internally for debility, gastroenteritis, and hemorrhage and externally for skin complaints, injuries, and neuralgia and throat infections. The essential oil is used in aromatherapy.<ref>{{cite web|title=Apple Geranium |url=http://www.naturalmedicinalherbs.net/herbs/p/pelargonium-odoratissimum=apple-geranium.php |publisher=Natural Medicinal Herbs}}</ref>

==== Pets ====

According to the ASPCA, these plants are toxic to cats, dogs, and horses.<ref>{{cite web |url=https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/geranium |title=Pet Care: Animal Poison Control: Toxic and Non-Toxic Plants: Geranium |publisher=American Society for the Prevention of Cruelty to Animals}}</ref>

=== Chemistry === Pelargonin (pelargonidin 3,5-O-diglucoside) is a petal pigment of the scarlet pelargonium.<ref>{{cite journal|last1=Saunders Currey|first1=Geoffrey|year=1922|title=The Colouring Matter of the Scarlet Pelargonium|url=https://zenodo.org/record/2077799| journal=J. Chem. Soc., Trans.|volume=121| pages=319–323|doi=10.1039/CT9222100319|doi-access=free}}</ref>

== In culture == Chemist John Dalton realized that he was color blind in 1794 when he heard others describe the color of the flowers of the pink ''Pelargonium zonale''<ref>{{cite journal|last=Hunt|first=D. M.|author2=K. S. Dulai |author3=J. K. Bowmaker|author4= J. D. Mollon|title=The chemistry of John Dalton's color blindness|journal=Science|year=1995|volume=267|issue=5200|pages=984–988|doi=10.1126/science.7863342|pmid=7863342|bibcode=1995Sci...267..984H|s2cid=6764146}}</ref> as pink or red, when to him it looked either pink or blue.<ref>{{cite journal|last=Dalton|first=John|title=Extraordinary facts relating to the vision of colours: with observations.|journal=Memoirs of the Literary and Philosophical Society of Manchester|year=1798|volume=5|pages=28–45}}</ref>

== Notes == {{notelist}}

== References == {{Reflist|30em|refs= *<ref name="patentCA 2704584">{{cite patent |url=http://www.google.com/patents/CA2704584C?cl=en |title=Flower pigmentation in pelargonium hortorum |country=CA |number=2704584 |pubdate=October 29, 2013 |status=grant |gdate= |fdate=Nov 14, 2008 |pridate= |inventor=Hanes, Mitchell E. |invent1= |invent2= |assign1= |assign2= |class=}}</ref> <ref name=powo>{{cite web |title=''Pelargonium'' L'Hér. ex Aiton |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30302759-2 |website=Plants of the World Online |publisher=Royal Botanic Gardens, Kew |access-date=2 August 2020}}</ref>

*<ref name=PPage>[http://www.pelargonium.si/ The Pelargonium Page]</ref> }}

== Bibliography ==

=== Books === {{refbegin|40em}} * {{cite book|last1=Bakker |first1=F. T. |last2=Culham |first2=A. |last3=Gibby |first3=M. |author-link3=Mary Gibby|chapter=Chapter16. Phylogenetics and diversification in Pelargonium |editor1-last=Hollingsworth |editor1-first=P. |editor2-last=Bateman |editor2-first=R. |editor3-last=Gornall |editor3-first=R. |title=Molecular Systematics and Plant Evolution |year=1999 |publisher=CRC Press |isbn=978-0-7484-0908-2 |doi=10.1201/9781439833278.ch16 |pages=353–374 |doi-broken-date=1 July 2025 |name-list-style=amp}} * {{cite book|last1=Boddy|first1=Kasia|title=Geranium|date=2013|publisher=Reaktion Books|location=London|isbn=9781780230580|url=https://books.google.com/books?id=24eoWcnoyfcC|access-date=31 July 2015}} * {{cite book|last1=Butterfield|first1=Harry Morton|title=Geraniums and pelargoniums for the home garden|date=1953|publisher=University of California|location=Berkeley|url=https://archive.org/details/geraniumspelargo12butt|access-date=23 July 2015}} * {{cite book|editor1-last=Lis-Balchin|editor1-first=Maria|title=Geranium and pelargonium: the genera geranium and pelargonium|date=2002|publisher=Taylor & Francis|location=London|isbn=978-0-415-28487-5|url=https://books.google.com/books?id=-bR8GxQ6BU0C|access-date=12 July 2015}} * {{cite book |last=Mabberley |first=David J |title=Mabberley's Plant-Book |year=2013 |publisher=Cambridge University Press |isbn=978-1107782594 |chapter-url=https://books.google.com/books?id=ZFFgAgAAQBAJ&pg=PT641 |chapter=Pelargonium |page=641 |edition=3 |access-date=17 August 2014 }} * {{cite book|last1=Taylor|first1=Judith M.|title=Visions of Loveliness: Great Flower Breeders of the Past|date=2014|publisher=Ohio University Press|isbn=9780804040624|url=https://books.google.com/books?id=RWuZBgAAQBAJ|access-date=23 July 2015}} * {{cite book|author1=van der Walt |author2=Vorster |others=Illustrated by Ellaphie Ward-Hilhorst |title=Pelargoniums of Southern Africa (3 vols) |date=1971–1988 |publisher=Purnell |location=Cape Town & Johannesburg |name-list-style=amp}} * {{cite book|last1=Wilkinson|first1=Ann|title=The Passion for Pelargoniums. How They Found Their Place in the Garden|date=2007|publisher=The History Press|location=Stroud|isbn=9780752496061|url=https://books.google.com/books?id=6787AwAAQBAJ|access-date=12 July 2015}}

==== Historical ==== * {{cite book |url=http://bibdigital.rjb.csic.es/ing/Libro.php?Libro=1386 |last=Dillenius |first=Johann Jakob |author-link=Dillenius |title=Hortus Elthamensis seu Plantarum Rariorum ... |publisher=Sumptibus Auctoris |location=London |date=1732 |access-date=26 July 2015 |language=la |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304205341/http://bibdigital.rjb.csic.es/ing/Libro.php?Libro=1386 |url-status=dead }} ** [http://gallica.bnf.fr/ark:/12148/bpt6k96818j ''Hortus Elthamensis''] on Gallica * {{cite book |url=https://www.biodiversitylibrary.org/bibliography/669#/summary |last=Linnaeus |first=Carl |author-link=Carl Linnaeus |title=Species Plantarum, ... |publisher=Impensis Laurentii Salvii |location=Stockholm |date=1753 |doi=10.5962/bhl.title.669 |language=la }} * {{cite book |url=https://www.biodiversitylibrary.org/bibliography/102247#/summary |last=Sweet |first=Robert |author-link=Robert Sweet (botanist) |title=Geraniaceae: The Natural Order of Gerania |volume=I |publisher=James Ridgeway |location=Piccadilly |date=1822 |doi=10.5962/bhl.title.102247 |hdl=2027/gri.ark:/13960/t61580v6m }} * {{cite book |url=https://books.google.com/books?id=ZTJCAAAAYAAJ |last1=Dauthenay |first1=Henri |title=Les Géraniums (Pelargonium zonale & inquinans): description et culture ... |publisher=Octave Doin |location=Paris |date=1897 |access-date=12 July 2015 |language=fr }} * {{cite encyclopedia |url=https://www.biodiversitylibrary.org/bibliography/29309#/summary |last=Bailey |first=L.H. |author-link=L.H.Bailey |title=The Cyclopedia of American Horticulture |format=4 vols. |publisher=Macmillan |location=New York |date=1906 |orig-year=1900 |edition=5th |doi=10.5962/bhl.title.29309 |doi-access=free }} * {{cite encyclopedia |url=https://www.biodiversitylibrary.org/bibliography/23351#/summary |last=Bailey |first=L.H. |author-link=L.H.Bailey |title=The Standard Cyclopedia of Horticulture |format=6 vols. |publisher=Macmillan |location=New York |date=1919 |orig-year=1900 |edition=3rd |doi=10.5962/bhl.title.23351 |doi-access=free }} {{refend}}

=== Articles and theses === {{refbegin|40em}} * {{cite journal |last1=Aedo |first1=Carlos |last2=Garmendia |first2=Félix Muñoz |title=Some Notes on the Sectional Nomenclature of Geranium (Geraniaceae) |journal=Taxon |volume=45 |issue=1 |date=Feb 1996 |pages=104–106 |doi=10.2307/1222593 |jstor=1222593 |bibcode=1996Taxon..45..104A |name-list-style=amp}} * {{cite journal |last1=Bakker |first1=Freek T. |last2=Culham |first2=Alastair |last3=Pankhurst |first3=Clive E. |last4=Gibby |first4=Mary |author-link4=Mary Gibby |title=Mitochondrial and chloroplast DNA-based phylogeny of Pelargonium (Geraniaceae) |journal=Am. J. Bot. |date=May 2000 |volume=87 |issue=5 |pages=727–734 |ref={{harvid|Bakker et al|2000}} |doi=10.2307/2656859 |jstor=2656859 |pmid=10811797 |name-list-style=amp}} * {{cite journal |last1=Bakker |first1=Freek T. |last2=Culham |first2=Alastair |last3=Hettiarachi |first3=Priyani |last4=Touloumenidou |first4=Tasoula |last5=Gibby |first5=Mary |author-link5=Mary Gibby |title=Phylogeny of Pelargonium (Geraniaceae) based on DNA sequences from three genomes |journal=Taxon |volume=53 |issue=1 |date=Feb 2004 |pages=17–28 |url=http://edepot.wur.nl/37026 |doi=10.2307/4135485 |jstor=4135485 |bibcode=2004Taxon..53Q..17B |name-list-style=amp |url-access=subscription}} * {{cite thesis |last=Lalli |first=Jacqueline Yolande Yvette |date=2005 |title=In Vitro Pharmacological Properties and Composition of Leaf Essential Oils and Extracts of Selected Indigenous Pelargonium (Geraniaceae) Species |type=MPharm |publisher=University of the Witwatersrand |url=http://wiredspace.wits.ac.za/bitstream/handle/10539/1690/Dissertation.pdf |access-date=7 August 2017}} * {{cite journal |last1=Röschenbleck |first1=J |last2=Albers |first2=F |last3=Müller |first3=K |last4=Weinl |first4=S |last5=Kudla |first5=J |title=Phylogenetics, character evolution and a subgeneric revision of the genus Pelargonium (Geraniaceae) |journal=Phytotaxa |date=11 February 2014 |volume=159 |issue=2 |pages=31–76 |url=http://www.mapress.com/phytotaxa/content/2014/f/p00159p076f.pdf |ref={{harvid|Roschenbleck et al|2014}} |name-list-style=amp |doi=10.11646/phytotaxa.159.2.1 |bibcode=2014Phytx.159...31R}} * {{cite journal |last1=van der Walt |first1=J.J.A. |title=Notes on the nomenclature of Pelargonium Geraniaceae |journal=Journal of South African Botany |date=1979 |volume=45 |issue=3 |pages=377–380 |doi=10.5962/p.396918 |url=http://eurekamag.com/research/006/000/006000979.php |access-date=14 July 2015}} * {{cite journal |last1=van der Walt |first1=J.J.A. |last2=Vorster |first2=P.J. |title=Typification of the Genus Pelargonium L'Hérit. (Fam. Geraniaceae) |journal=Taxon |date=February 1981 |volume=30 |issue=1 |pages=307 |doi=10.2307/1219408 |jstor=1219408 |bibcode=1981Taxon..30..307V |name-list-style=amp}} {{refend}}

=== Societies === {{refbegin|40em}} * {{cite web |last1=ISHS |title=International Society for Horticultural Science |url=http://www.ishs.org/ |access-date=13 July 2015 |date=2015 |author1-link=International Society for Horticultural Science}} * {{cite web |last1=RHS |title=Royal Horticultural Society |url=https://www.rhs.org.uk/ |access-date=19 June 2015 |date=2015 |author1-link=Royal Horticultural Society}} * {{cite web |last1=PAGS |title=The Pelargonium & Geranium Society |url=https://thepags.org/ |access-date=25 Jan 2023 |date=2023}} * {{cite web |last1=AGS |title=Australian Geranium Society |url=http://www.australiangeraniumsociety.org.au/ |access-date=8 July 2015 |date=2014}} * {{cite web |last1=HSA |title=The Herb Society of America |url=http://www.herbsociety.org/ |access-date=12 July 2015 |date=2015 |archive-date=24 September 2015 |archive-url=https://web.archive.org/web/20150924025744/http://www.herbsociety.org/factsheets/Pelargonium%20Guide.pdf |url-status=bot: unknown}}** * {{cite web |last1=Amadio |first1=Marisa |title=The Geraniaceae Group |url=http://www.geraniaceae-group.org/ |access-date=13 July 2015 |date=2015}} {{refend}}

== External links == {{Commons category}} * [http://www.pelargonium.si/ ''The Pelargonium Page'': descriptions of botanical species with plant and habitat photos, illustrations and literature] * [http://www.pacificbulbsociety.org/pbswiki/index.php/Pelargonium Pacific Bulb Society: Pelargonium (tuberous species)]

Category:Pelargonium Category:Geraniales genera Category:Garden plants Category:Medicinal plants Category:Taxa named by Charles Louis L'Héritier de Brutelle