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{{Short description|Hybrids of orchids}}
{{Hatnote|Not to be confused with [[Grex (biology)]], a mass of single-celled amoebae.}}
{{wikt|grex}}
[[File:Lycaste grex hera 1.jpg|thumb|× ''Lycamerlycaste'' Hera gx is a grex of orchid hybrids in the nothogenus × ''Lycamerlycaste'' J.M.H.Shaw. It consists of hybrids between members of a grex (× ''Lycamerlycaste'' Brugensis gx) and a species (''[[Lycaste cruenta]]'' Lindl.).]]
[[File:Lycaste grex hera 1.jpg|thumb|× ''Lycamerlycaste'' Hera gx is a grex of orchid hybrids in the nothogenus × ''Lycamerlycaste'' J.M.H.Shaw. It consists of hybrids between members of a grex (× ''Lycamerlycaste'' Brugensis gx) and a species (''[[Lycaste cruenta]]'' Lindl.).]]
The term '''grex''' (pl. greges or grexes, abbreviation gx), derived from the [[Latin language|Latin]] noun ''grex, gregis'' meaning 'flock', has been coined to expand [[botanical nomenclature]] to describe hybrids of [[orchids]], based solely on their parentage.<ref>{{harv|Brickell et al. 2009|Article 4.1|ref=Brickell}}</ref> Grex names are one of the three categories of plant names governed by the [[International Code of Nomenclature for Cultivated Plants]]; within a grex the [[Cultivar group|Groups]] category can be used to refer to plants by their shared characteristics (rather than by their parentage), and individual orchid plants can be selected (and propagated) and named as [[cultivar]]s.<ref>{{harv|Brickell et al. 2009|p=x|ref=Brickell}}</ref><ref>{{citation |url=http://www.hortax.org.uk/grex.html |title=HORTAX: Cultivated Plant Taxonomy Group |accessdate=30 July 2016}}</ref>
The term '''''grex''''' (plural '''''greges''''' or '''''grexes'''''; abbreviation '''gx'''), derived from the [[Latin language|Latin]] noun {{lang|la|grex}}, {{lang|la|gregis}}, meaning 'flock', has been expanded in [[botanical nomenclature]] to describe hybrids of [[orchids]], based solely on their parentage.<ref>{{harv|Brickell et al. 2009|loc=Article 4.1|ref=Brickell}}</ref> Grex names are one of the three categories of plant names governed by the [[International Code of Nomenclature for Cultivated Plants]]; within a grex the ''[[cultivar group]]'' category can be used to refer to plants by their shared characteristics (rather than by their parentage), and individual orchid plants can be selected (and propagated) and named as [[cultivar]]s.<ref>{{harv|Brickell et al. 2009|p=x|ref=Brickell}}</ref><ref>{{citation |url=http://www.hortax.org.uk/grex.html |title=HORTAX: Cultivated Plant Taxonomy Group |access-date=30 July 2016 |archive-url=https://web.archive.org/web/20160817152253/http://www.hortax.org.uk/grex.html |archive-date=17 August 2016 |url-status=dead }}</ref>

⚫
When the name of a grex is first established, a description is required that specifies two particular parents, where each parent is specified either as a [[species]] (or [[nothospecies]]) or as a grex.<ref>{{harv|Brickell et al. 2009|Article 4|ref=Brickell}}</ref> The grex name then applies to all [[Hybrid (biology)|hybrids]] between those two parents. There is a permitted exception if the full name of one of the parents is known but the other is known only to genus level or nothogenus level.<ref>{{harv|Brickell et al. 2009|Article 27.4|ref=Brickell}}</ref>

⚫
New grex names are now established by the [[Royal Horticultural Society]], which receives applications from orchid hybridizers.<ref>{{harv|Brickell et al. 2009|Appendix 1|ref=Brickell}}</ref><ref>{{citation |url=https://www.rhs.org.uk/plants/plantsmanship/plant-registration/Orchid-hybrid-registration |title=Orchid hybrid registration |publisher=Royal Horticultural Society |accessdate=3 August 2016}}</ref>

==Orchids==
In the rare case where a nothospecies name already exists, then a differing grex name cannot be established.<ref>{{harv|Brickell et al. 2009|Article 23.5|ref=Brickell}}</ref> Technically a grex differs from a nothospecies in that a nothospecies includes any potential combinations of [[backcrossing|back-crosses]] <ref>{{harv|Brickell et al. 2009|Note 1 page 37|ref=Brickell}}</ref> The nothospecies naming convention is limited to identifying that, in some combination, two species are in the background of a nothospecies. In contrast, grex genealogies within Orchids are well known and documented and therefore each successive crossing of a grex to either of the original parent species, results in a new grex with a new genealogy. In both of those example, only two species are known or suspect in the background of the offspring, but grex names document to what degree.


==Botanical nomenclature of hybrids==
==Botanical nomenclature of hybrids==
The horticultural nomenclature of grexes exists within the framework of the botanical nomenclature of hybrid plants. Interspecific hybrids occur in nature, and are treated under the [[International Code of Nomenclature for algae, fungi, and plants]] as [[nothospecies]], ('notho' indicating hybrid). They can optionally be given Linnean binomials with a multiplication sign "×" before the species epithet,<ref>{{cite book |author=McNeill, J.; Barrie, F.R.; Buck, W.R.; Demoulin, V.; Greuter, W.; Hawksworth, D.L.; Herendeen, P.S.; Knapp, S.; Marhold, K.; Prado, J.; Prud'homme Van Reine, W.F.; Smith, G.F.; Wiersema, J.H.; Turland, N.J. |year=2012 |volume=Regnum Vegetabile 154 |title=International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011 |publisher=A.R.G. Gantner Verlag KG |isbn=978-3-87429-425-6 |url=http://www.iapt-taxon.org/nomen/main.php?page=title }} Article H1</ref> for example ''Crataegus'' × ''media''. An offspring of the nothospecies, either with the nothospecies or any of the parental species as the other parent, has the same nothospecific name. The nothospecific binomial is an alias for a list of the ancestral species, whether the ancestry is precisely known or not.
The horticultural nomenclature of grexes exists within the framework of the botanical nomenclature of hybrid plants. Interspecific hybrids occur in nature, and are treated under the [[International Code of Nomenclature for algae, fungi, and plants]] as [[nothospecies]], ('notho' indicating hybrid). They can optionally be given Linnean [[Binomial nomenclature|binomials]] with a multiplication sign "×" before the species epithet<ref>{{harv|McNeill et al. 2012|loc=Article H1|ref=McNeill}}</ref> for example ''Crataegus'' × ''media''. An offspring of a nothospecies, either with a member of the same nothospecies or any of the parental species as the other parent, has the same nothospecific name. The nothospecific binomial is an alias for a list of the ancestral species, whether the ancestry is precisely known or not.


For example:
For example:
* a hybrid between ''[[Cattleya warscewiczii]]'' <small>Rchb.f. 1854</small> and ''[[Cattleya aurea]]'' <small>Linden 1883</small> can be called ''Cattleya'' ×''hardyana'' <small>Sander 1883</small> or simply ''Cattleya hardyana''. An offspring of a ''Cattleya'' × ''hardyana'' [[Pollenizer|pollenized]] by another ''Cattleya'' × ''hardyana'' would also be called ''Cattleya'' × ''hardyana''. ''Cattleya'' × ''hardyana'' would also be the name of an offspring of a ''Cattleya'' × ''hardyana'' pollenized by either a ''Cattleya warscewiczii'' or a ''Cattleya aurea'', or an offspring of either a ''Cattleya warscewiczii'' or a ''Cattleya aurea'' pollenized by a ''Cattleya'' × ''hardyana''.
* a hybrid between ''[[Cattleya warscewiczii]]'' <small>Rchb.f. 1854</small> and ''[[Cattleya aurea]]'' <small>Linden 1883</small> can be called ''Cattleya'' × ''hardyana'' <small>Sander 1883</small> or simply ''Cattleya hardyana''. An offspring of a ''Cattleya'' × ''hardyana'' [[Pollenizer|pollenized]] by another ''Cattleya'' × ''hardyana'' would also be called ''Cattleya'' × ''hardyana''. ''Cattleya'' × ''hardyana'' would also be the name of an offspring of a ''Cattleya'' × ''hardyana'' pollenized by either a ''Cattleya warscewiczii'' or a ''Cattleya aurea'', or an offspring of either a ''Cattleya warscewiczii'' or a ''Cattleya aurea'' pollenized by a ''Cattleya'' × ''hardyana''.
⚫
* [[× Brassocattleya|× ''Brassocattleya'']] is a nothogenus including all hybrids between ''[[Brassavola]]'' and ''[[Cattleya]]''. It includes the species ''Brassocattleya'' × ''arauji'', also known simply as ''Brassocattleya arauji'', which includes all hybrids between ''[[Brassavola tuberculata]]'' and ''[[Cattleya forbesii]]''.<ref>{{citation |url=http://apps.kew.org/wcsp/namedetail.do?name_id=24325 |title=World Checklist of Selected Plant Families |access-date=2 August 2016 }}{{Dead link|date=June 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

⚫
* × ''[[Brassocattleya]]'' is a nothogenus including all hybrids between ''[[Brassavola]]'' and ''[[Cattleya]]''. It includes the species ''Brassocattleya'' × ''arauji'', also known simply as ''Brassocattleya arauji'', which includes all hybrids between ''[[Brassavola tuberculata]]'' and ''[[Cattleya forbesii]]''.<ref>{{citation |url=http://apps.kew.org/wcsp/namedetail.do?name_id=24325 |title=World Checklist of Selected Plant Families |accessdate=2 August 2016}}</ref>


An earlier term was '''nothomorph''' for subordinate taxa to nothospecies. Since the 1982 meeting of the [[International Botanical Congress]], such subordinate taxa are considered [[Variety (botany)|varieties]] (nothovars).
An earlier term was '''nothomorph''' for subordinate taxa to nothospecies. Since the 1982 meeting of the [[International Botanical Congress]], such subordinate taxa are considered [[Variety (botany)|varieties]] (nothovars).


==Horticultural treatment of greges==
==Horticultural treatment==
Because many interspecific (and even intergeneric) barriers to hybridization in the Orchidaceae are maintained in nature only by pollinator behavior, it is easy to produce complex interspecific and even intergeneric hybrid orchid seeds: all it takes is a human motivated to use a toothpick, and proper care of the mother plant as it develops a seed pod. Germinating the seeds and growing them to maturity is more difficult, however.
Because many interspecific (and even intergeneric) barriers to hybridization in the Orchidaceae are maintained in nature only by pollinator behavior, it is easy to produce complex interspecific and even intergeneric hybrid orchid seeds: all it takes is a human motivated to use a toothpick, and proper care of the mother plant as it develops a seed pod. Germinating the seeds and growing them to maturity is more difficult, however.


When a hybrid cross is made, all of the seedlings grown from the resulting seed pod are considered to be in the same grex. Any additional plants produced from the hybridization of the same two parents (members of the same species or greges as the original parents) also belong to the grex. [[Reciprocal cross]]es are included within the same grex.<ref>{{harv|Brickell et al. 2009|Article 4 Note 2|ref=Brickell}}</ref> If two members of the same grex produce offspring, the offspring receive the same grex name as the parents.
When a hybrid cross is made, all of the seedlings grown from the resulting seed pod are considered to be in the same grex. Any additional plants produced from the hybridization of the same two parents (members of the same species or greges as the original parents) also belong to the grex. [[Reciprocal cross]]es are included within the same grex.<ref>{{harv|Brickell et al. 2009|loc=Article 4 Note 2|ref=Brickell}}</ref> If two members of the same grex produce offspring, the offspring receive the same grex name as the parents.


If a parent of a grex becomes a [[synonym (taxonomy)|synonym]], any grex names that were established by specifying the synonym are not necessarily discarded; the grex name that was published first is used (the [[Principle of Priority]]).<ref>{{harv|Brickell et al. 2009|Article 4.3|ref=Brickell}}</ref>
If a parent of a grex becomes a [[synonym (taxonomy)|synonym]], any grex names that were established by specifying the synonym are not necessarily discarded; the grex name that was published first is used (the [[principle of priority]]).<ref>{{harv|Brickell et al. 2009|loc=Article 4.3|ref=Brickell}}</ref>


All of the members of a specific grex may be loosely thought of as "sister plants", and just like the brothers and sisters of any family, may share many traits or look quite different from one another. This is due to the randomization of genes passed on to progeny during [[sexual reproduction]]. The hybridizer who created a new grex normally chooses to register the grex with a registration authority, thus creating a new grex name, but there is no requirement to do this. Individual plants may be given [[cultivar]] names to distinguish them from siblings in their grex. Cultivar names are usually given to superior plants with the expectation of propagating that plant; all genetically identical copies of a plant, regardless of method of propagation (divisions or clones) share a cultivar name.
All of the members of a specific grex may be loosely thought of as "sister plants", and just like the brothers and sisters of any family, may share many traits or look quite different from one another. This is due to the randomization of genes passed on to progeny during [[sexual reproduction]]. The hybridizer who created a new grex normally chooses to register the grex with a registration authority, thus creating a new grex name, but there is no requirement to do this. Individual plants may be given [[cultivar]] names to distinguish them from siblings in their grex. Cultivar names are usually given to superior plants with the expectation of propagating that plant; all genetically identical copies of a plant, regardless of method of propagation (divisions or clones) share a cultivar name.


== Naming ==
⚫
The grex name differs from a species name in that the gregaric part of the name is capitalized, is not italicized, and may consist of more than one word (limited to 30 characters in total, excluding spaces).<ref>{{harv|Brickell et al. 2009|Article 21.13|ref=Brickell}}</ref>
{{multiple image |direction=horizontal |header=Two named cultivars from the same grex |image1=Cymbidium Kirby Lesh 'Pink Ice'.jpg |caption1=''Cymbidium'' Kirby Lesh 'Pink Ice' |image2=Cymbidium Kirby Lesh 'Lonsdale'.jpg |caption2=''Cymbidium'' Kirby Lesh 'Lonsdale'}}
The rules for the naming of greges are defined by the ''[[International Code of Nomenclature for Cultivated Plants]]'' (ICNCP).
⚫
The grex name differs from a species name in that the gregaric part of the name is capitalized, is not italicized, and may consist of more than one word (limited to 30 characters in total, excluding spaces).<ref>{{harv|Brickell et al. 2009|loc=Article 21.13|ref=Brickell}}</ref>
Furthermore, names of greges are to be in a living language rather than Latin.

⚫
For example: an artificially produced hybrid between ''Cattleya warscewiczii'' and ''C.&nbsp;dowiana'' (or ''C.&nbsp;aurea'', which the RHS, the international orchid hybrid registration authority, considers to be a synonym of ''C. dowiana'') is called ''C.''&nbsp;Hardyana&nbsp;(1896) gx.<ref>{{Cite web |title=''Cattleya'' Hardyana (1896) |website=The International Orchid Register |publisher=Royal Horticultural Society |url=https://apps.rhs.org.uk/horticulturaldatabase/orchidregister/orchiddetails.asp?ID=45739 |access-date=2023-12-18 }}</ref> An artificially produced seedling that results from pollinating a ''C.''&nbsp;Hardyana&nbsp;(1896) gx with another ''C.''&nbsp;Hardyana&nbsp;(1896) gx is also a ''C.''&nbsp;Hardyana&nbsp;(1896) gx.{{citation needed|date=August 2016}} However, the hybrid produced between ''Cattleya''&nbsp;Hardyana&nbsp;(1896) gx and ''C.&nbsp;dowiana'' is not ''C.''&nbsp;Hardyana&nbsp;(1896) gx, but ''C.''&nbsp;Prince John gx.<ref>{{Cite web |title=''Cattleya'' Prince John |website=The International Orchid Register |publisher=Royal Horticultural Society |url=https://apps.rhs.org.uk/horticulturaldatabase/orchidregister/orchiddetails.asp?ID=20284 |access-date=2023-12-18 }}</ref> In summary:
⚫
*''C.&nbsp;warscewiczii'' × ''C.&nbsp;dowiana'' → ''C.''&nbsp;Hardyana (1896) gx
*''C.''&nbsp;Hardyana (1896) gx × ''C.&nbsp;warscewiczii'' → ''C.''&nbsp;Eleanor (1918) gx<ref>{{Cite web |title=''Cattleya'' Eleanor (1918) |website=The International Orchid Register |publisher=Royal Horticultural Society |url=https://apps.rhs.org.uk/horticulturaldatabase/orchidregister/orchiddetails.asp?ID=32842 |access-date=2023-12-18 }}</ref>
⚫
*''C.&nbsp;dowiana'' × ''C.''&nbsp;Hardyana (1896) gx → ''C.''&nbsp;Prince John gx

== Registration ==
⚫
When the name of a grex is first established, a description is required that specifies two particular parents, where each parent is specified either as a [[species]] (or [[nothospecies]]) or as a grex.<ref>{{harv|Brickell et al. 2009|loc=Article 4|ref=Brickell}}</ref> The grex name then applies to all [[Hybrid (biology)|hybrids]] between those two parents. There is a permitted exception if the full name of one of the parents is known but the other is known only to genus level or nothogenus level.<ref>{{harv|Brickell et al. 2009|loc=Article 27.4|ref=Brickell}}</ref>


⚫
New grex names are now established by the [[Royal Horticultural Society]], which receives applications from orchid hybridizers.<ref>{{harv|Brickell et al. 2009|loc=Appendix 1|ref=Brickell}}</ref><ref>{{citation |url=https://www.rhs.org.uk/plants/plantsmanship/plant-registration/Orchid-hybrid-registration |title=Orchid hybrid registration |publisher=Royal Horticultural Society |access-date=3 August 2016}}</ref>
⚫
For example: an artificially produced hybrid between ''Cattleya warscewiczii'' and ''C.&nbsp;dowiana'' (or ''C.&nbsp;aurea'', which the RHS, the international orchid hybrid registration authority, considers to be a synonym of ''C. dowiana'') is called ''C.''&nbsp;Hardyana&nbsp;gx. An artificially produced seedling that results from pollinating a ''C.''&nbsp;Hardyana gx with another ''C.''&nbsp;Hardyana gx is also a ''C.''&nbsp;Hardyana gx.{{cn|date=August 2016}} However, the hybrid produced between ''Cattleya''&nbsp;Hardyana gx and ''C.&nbsp;dowiana'' is not ''C.''&nbsp;Hardyana gx, but ''C.''&nbsp;Prince John gx. In summary:
*''C.''&nbsp;Hardyana gx = ''C.&nbsp;warscewiczii'' × ''C.&nbsp;dowiana''
⚫
*''C.''&nbsp;Eleanor gx = ''C.''&nbsp;Hardyana gx × ''C.&nbsp;warscewiczii''
⚫
*''C.''&nbsp;Prince John gx = ''C.&nbsp;dowiana'' × ''C.''&nbsp;Hardyana gx


==Grexes within nothospecies==
== Relationship with nothospecies ==
The concept of grex and nothospecies are similar, but not equivalent. While greges are only used within the orchid family, nothospecies are used for any plant (including orchids).
A grex and a nothospecies can have the same parentage, but are not equivalent because the nothospecies includes back-crosses and the grex does not.<ref name=B1>{{harv|Brickell et al. 2009|Article 23.5|ref=Brickell}}</ref> They can even have the same [[epithet (taxonomy)|epithet]] (distinguished by typography), although since January 2010 it is not permitted to publish such grex names if the nothospecies name already exists.<ref name=B1/>


Hybrids between a grex and a species/nothospecies are named as grexes, but this is not permitted if the nothospecies parent has the same parentage as the grex parent. That situation is a back-cross, and the nothospecies name is applied to the progeny.<ref name=B1/>
Furthermore, a grex and nothospecies differ in that a grex and a nothospecies can have the same parentage, but are not equivalent because the nothospecies includes back-crosses and the grex does not.<ref name=B1>{{harv|Brickell et al. 2009|loc=Article 23.5|ref=Brickell}}</ref> They can even have the same [[epithet]], distinguished by typography (see [[botanical name]] for explanation of epithets), although since January 2010 it is not permitted to publish such grex names if the nothospecies name already exists.<ref name=B1/>


Hybrids between a grex and a species/nothospecies are named as greges, but this is not permitted if the nothospecies parent has the same parentage as the grex parent. That situation is a back-cross, and the nothospecies name is applied to the progeny.<ref name=B1/>
==See also==
* {{portal-inline|Plants}}


==References==
==References==
{{Reflist}}
{{Reflist|24em}}


==Bibliography==
== Bibliography ==
{{refbegin}}
*{{citation |author1=Brickell, C.D. |author2=Alexander, C. |author3=David, J.C. |author4=Hetterscheid, W.L.A. |author5=Leslie, A.C. |author6=Malecot, V. |author7=Jin, X. |author8=Cubey, J.J. |year=2009 |title=International Code of Nomenclature for Cultivated Plants (ICNCP or Cultivated Plant Code) incorporating the Rules and Recommendations for naming plants in cultivation, Eighth Edition, Adopted by the International Union of Biological Sciences International Commission for the Nomenclature of Cultivated Plants |publisher=International Association for Plant Taxonomy and International Society for Horticultural Science |url=http://www.actahort.org/chronica/pdf/sh_10.pdf |isbn=978-90-6605-662-6 |ref=Brickell}}
*{{citation |author1=Brickell, C.D. |author2=Alexander, C. |author3=David, J.C. |author4=Hetterscheid, W.L.A. |author5=Leslie, A.C. |author6=Malecot, V. |author7=Jin, X. |author8=Cubey, J.J. |year=2009 |title=International Code of Nomenclature for Cultivated Plants (ICNCP or Cultivated Plant Code) incorporating the Rules and Recommendations for naming plants in cultivation, Eighth Edition, Adopted by the International Union of Biological Sciences International Commission for the Nomenclature of Cultivated Plants |publisher=International Association for Plant Taxonomy and International Society for Horticultural Science |url=http://www.actahort.org/chronica/pdf/sh_10.pdf |isbn=978-90-6605-662-6 |ref=Brickell}}
*{{citation |author1=McNeill, J. |author2=Barrie, F.R. |author3=Buck, W.R. |author4=Demoulin, V. |author5=Greuter, W. |author6=Hawksworth, D.L. |author7=Herendeen, P.S. |author8=Knapp, S. |author9=Marhold, K. |author10=Prado, J. |author11=Prud'homme Van Reine, W.F. |author12=Smith, G.F. |author13=Wiersema, J.H. |author14=Turland, N.J. |year=2012 |volume=Regnum Vegetabile 154 |title=International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011 |publisher=A.R.G. Gantner Verlag KG |isbn=978-3-87429-425-6 |url=http://www.iapt-taxon.org/nomen/main.php?page=title |ref=McNeill}}
* {{cite web|last1=RHS|author-link=Royal Horticultural Society|title=Search The International Orchid Register|url=http://apps.rhs.org.uk/horticulturaldatabase/orchidregister/orchidregister.asp|publisher=[[Royal Horticultural Society]]|access-date=28 November 2017|date=2016}}
{{refend}}


==External links ==
==External links ==
* [https://www.rhs.org.uk/about-the-rhs/pdfs/publications/orchid-hybrid-lists/web-orchid-reg-nhl-1306-jan-mar-2014 "Quarterly Supplement To The International Register And Checklist Of Orchid Hybrids (Sander’s List) January – March 2014 Registrations" Distributed with ''The Orchid Review'' '''122'''(1306) (June 2014), The Royal Horticultural Society.]
* [https://www.rhs.org.uk/about-the-rhs/pdfs/publications/orchid-hybrid-lists/web-orchid-reg-nhl-1306-jan-mar-2014 "Quarterly Supplement To The International Register And Checklist Of Orchid Hybrids (Sander’s List) January – March 2014 Registrations" Distributed with ''The Orchid Review'' '''122'''(1306) (June 2014), The Royal Horticultural Society.]
* [http://apps.rhs.org.uk/horticulturaldatabase/orchidregister/orchidregister.asp Search the orchid register]
* [https://www.rhs.org.uk/plants/pdfs/plant-registration-forms/orchid-grex,-groups-and-cultivar-names-guidelines Guide lines and rules for composing grex, group and cultivar names. Summary of ICNCP rules and guidelines for Grex and Cultivar epithets.]
* [https://www.rhs.org.uk/plants/pdfs/plant-registration-forms/orchid-grex,-groups-and-cultivar-names-guidelines Guide lines and rules for composing grex, group and cultivar names. Summary of ICNCP rules and guidelines for Grex and Cultivar epithets.]
* {{cite book|last1=Gledhill|first1=David|title=The names of plants|date=2006|publisher=Cambridge University Press|location=Cambridge|isbn=0521866456|edition=4th|url=http://books.google.ca/books?id=NJ6PyhVuecwC|accessdate=16 October 2014}}


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[[Category:Botanical nomenclature]]
[[Category:Botanical nomenclature]]
[[Category:Orchid hybrids]]

Latest revision as of 20:23, 24 June 2024

Not to be confused with Grex (biology), a mass of single-celled amoebae.
Look up grex in Wiktionary, the free dictionary.
× Lycamerlycaste Hera gx is a grex of orchid hybrids in the nothogenus × Lycamerlycaste J.M.H.Shaw. It consists of hybrids between members of a grex (× Lycamerlycaste Brugensis gx) and a species (Lycaste cruenta Lindl.).

The term grex (plural greges or grexes; abbreviation gx), derived from the Latin noun grex, gregis, meaning 'flock', has been expanded in botanical nomenclature to describe hybrids of orchids, based solely on their parentage.[1] Grex names are one of the three categories of plant names governed by the International Code of Nomenclature for Cultivated Plants; within a grex the cultivar group category can be used to refer to plants by their shared characteristics (rather than by their parentage), and individual orchid plants can be selected (and propagated) and named as cultivars.[2][3]

Botanical nomenclature of hybrids

[edit]

The horticultural nomenclature of grexes exists within the framework of the botanical nomenclature of hybrid plants. Interspecific hybrids occur in nature, and are treated under the International Code of Nomenclature for algae, fungi, and plants as nothospecies, ('notho' indicating hybrid). They can optionally be given Linnean binomials with a multiplication sign "×" before the species epithet[4] for example Crataegus × media. An offspring of a nothospecies, either with a member of the same nothospecies or any of the parental species as the other parent, has the same nothospecific name. The nothospecific binomial is an alias for a list of the ancestral species, whether the ancestry is precisely known or not.

For example:

  • a hybrid between Cattleya warscewiczii Rchb.f. 1854 and Cattleya aurea Linden 1883 can be called Cattleya × hardyana Sander 1883 or simply Cattleya hardyana. An offspring of a Cattleya × hardyana pollenized by another Cattleya × hardyana would also be called Cattleya × hardyana. Cattleya × hardyana would also be the name of an offspring of a Cattleya × hardyana pollenized by either a Cattleya warscewiczii or a Cattleya aurea, or an offspring of either a Cattleya warscewiczii or a Cattleya aurea pollenized by a Cattleya × hardyana.
  • × Brassocattleya is a nothogenus including all hybrids between Brassavola and Cattleya. It includes the species Brassocattleya × arauji, also known simply as Brassocattleya arauji, which includes all hybrids between Brassavola tuberculata and Cattleya forbesii.[5]

An earlier term was nothomorph for subordinate taxa to nothospecies. Since the 1982 meeting of the International Botanical Congress, such subordinate taxa are considered varieties (nothovars).

Horticultural treatment

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Because many interspecific (and even intergeneric) barriers to hybridization in the Orchidaceae are maintained in nature only by pollinator behavior, it is easy to produce complex interspecific and even intergeneric hybrid orchid seeds: all it takes is a human motivated to use a toothpick, and proper care of the mother plant as it develops a seed pod. Germinating the seeds and growing them to maturity is more difficult, however.

When a hybrid cross is made, all of the seedlings grown from the resulting seed pod are considered to be in the same grex. Any additional plants produced from the hybridization of the same two parents (members of the same species or greges as the original parents) also belong to the grex. Reciprocal crosses are included within the same grex.[6] If two members of the same grex produce offspring, the offspring receive the same grex name as the parents.

If a parent of a grex becomes a synonym, any grex names that were established by specifying the synonym are not necessarily discarded; the grex name that was published first is used (the principle of priority).[7]

All of the members of a specific grex may be loosely thought of as "sister plants", and just like the brothers and sisters of any family, may share many traits or look quite different from one another. This is due to the randomization of genes passed on to progeny during sexual reproduction. The hybridizer who created a new grex normally chooses to register the grex with a registration authority, thus creating a new grex name, but there is no requirement to do this. Individual plants may be given cultivar names to distinguish them from siblings in their grex. Cultivar names are usually given to superior plants with the expectation of propagating that plant; all genetically identical copies of a plant, regardless of method of propagation (divisions or clones) share a cultivar name.

Naming

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Two named cultivars from the same grex
Cymbidium Kirby Lesh 'Pink Ice'
Cymbidium Kirby Lesh 'Lonsdale'

The rules for the naming of greges are defined by the International Code of Nomenclature for Cultivated Plants (ICNCP). The grex name differs from a species name in that the gregaric part of the name is capitalized, is not italicized, and may consist of more than one word (limited to 30 characters in total, excluding spaces).[8] Furthermore, names of greges are to be in a living language rather than Latin.

For example: an artificially produced hybrid between Cattleya warscewiczii and C. dowiana (or C. aurea, which the RHS, the international orchid hybrid registration authority, considers to be a synonym of C. dowiana) is called C. Hardyana (1896) gx.[9] An artificially produced seedling that results from pollinating a C. Hardyana (1896) gx with another C. Hardyana (1896) gx is also a C. Hardyana (1896) gx.[citation needed] However, the hybrid produced between Cattleya Hardyana (1896) gx and C. dowiana is not C. Hardyana (1896) gx, but C. Prince John gx.[10] In summary:

  • C. warscewiczii × C. dowiana → C. Hardyana (1896) gx
  • C. Hardyana (1896) gx × C. warscewiczii → C. Eleanor (1918) gx[11]
  • C. dowiana × C. Hardyana (1896) gx → C. Prince John gx

Registration

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When the name of a grex is first established, a description is required that specifies two particular parents, where each parent is specified either as a species (or nothospecies) or as a grex.[12] The grex name then applies to all hybrids between those two parents. There is a permitted exception if the full name of one of the parents is known but the other is known only to genus level or nothogenus level.[13]

New grex names are now established by the Royal Horticultural Society, which receives applications from orchid hybridizers.[14][15]

Relationship with nothospecies

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The concept of grex and nothospecies are similar, but not equivalent. While greges are only used within the orchid family, nothospecies are used for any plant (including orchids).

Furthermore, a grex and nothospecies differ in that a grex and a nothospecies can have the same parentage, but are not equivalent because the nothospecies includes back-crosses and the grex does not.[16] They can even have the same epithet, distinguished by typography (see botanical name for explanation of epithets), although since January 2010 it is not permitted to publish such grex names if the nothospecies name already exists.[16]

Hybrids between a grex and a species/nothospecies are named as greges, but this is not permitted if the nothospecies parent has the same parentage as the grex parent. That situation is a back-cross, and the nothospecies name is applied to the progeny.[16]

References

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  1. ^ (Brickell et al. 2009, Article 4.1)
  2. ^ (Brickell et al. 2009, p. x)
  3. ^ HORTAX: Cultivated Plant Taxonomy Group, archived from the original on 17 August 2016, retrieved 30 July 2016
  4. ^ (McNeill et al. 2012, Article H1)
  5. ^ World Checklist of Selected Plant Families, retrieved 2 August 2016[permanent dead link]
  6. ^ (Brickell et al. 2009, Article 4 Note 2)
  7. ^ (Brickell et al. 2009, Article 4.3)
  8. ^ (Brickell et al. 2009, Article 21.13)
  9. ^ "Cattleya Hardyana (1896)". The International Orchid Register. Royal Horticultural Society. Retrieved 2023-12-18.
  10. ^ "Cattleya Prince John". The International Orchid Register. Royal Horticultural Society. Retrieved 2023-12-18.
  11. ^ "Cattleya Eleanor (1918)". The International Orchid Register. Royal Horticultural Society. Retrieved 2023-12-18.
  12. ^ (Brickell et al. 2009, Article 4)
  13. ^ (Brickell et al. 2009, Article 27.4)
  14. ^ (Brickell et al. 2009, Appendix 1)
  15. ^ Orchid hybrid registration, Royal Horticultural Society, retrieved 3 August 2016
  16. ^ a b c (Brickell et al. 2009, Article 23.5)

Bibliography

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