Editing Form (botany)

{{Short description|Taxonomic rank in botanical nomenclature}}
{{About|the formal taxonomic term in botany|the use in zoology|Form (zoology)|the informal botanical grouping|Forma specialis}}
{{Biological classification}}
[[File:Abies procera 'Glauca' - 20101120-02.jpg|thumb|right|Seedlings of ''[[Abies procera]]'' sometimes arise that have attractive silvery-blue foliage. The name ''Abies procera'' Rehder forma ''glauca'' (Ravenscr.) Rehder has been created for these. However, if the plants are selectively propagated for the [[horticulture]] trade, a [[cultivar]] name is generally used instead.]]

In [[botanical nomenclature]], a '''''form''''' (''forma'', plural ''formae'') is one of the "secondary" [[taxonomic rank]]s, below that of [[Variety (biology)|variety]], which in turn is below that of species; it is an [[infraspecific taxon]].<ref>{{cite book |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 }} Chapter I. Article 4</ref> If more than three ranks are listed in describing a taxon, the "classification" is being specified, but only three parts make up the "name" of the taxon: a [[genus]] name, a [[specific name (botany)|specific epithet]], and an [[infraspecific epithet]].

The abbreviation "f." or the full "forma" should be put before the infraspecific epithet to indicate the rank. It is not italicised.

For example:
* ''[[Acanthocalycium]] spiniflorum'' f. ''klimpelianum'' or
** ''Acanthocalycium spiniflorum'' forma ''klimpelianum'' (Weidlich & Werderm.) Donald
* ''[[Crataegus aestivalis]]'' (Walter) Torr. & A.Gray var. ''cerasoides'' Sarg. f. ''luculenta'' Sarg. is a classification of a plant whose name is:
** ''Crataegus aestivalis'' (Walter) Torr. & A.Gray f. ''luculenta'' Sarg.

A form usually designates a group with a noticeable morphological deviation. The usual taxonomic practice is that the individuals classified within the form are not necessarily known to be closely related (they may not form a [[clade]]).<ref>{{citation |author1=Hamilton, C.W. |author2=Reichard, S.H. |year=1992 |title=Current Practice in the Use of Subspecies, Variety, and Forma in the Classification of Wild Plants |journal=Taxon |volume=41 |issue=3 |pages=485–498 |jstor=1222819 |doi=10.2307/1222819 }}</ref> For instance, white-flowered plants of species that usually have coloured flowers can be grouped and named (e.g., as "f. ''alba''"). '''''Formae apomicticae''''' are sometimes named among plants that reproduce asexually, by [[apomixis]]. There are theoretically countless numbers of forms based on minor genetic differences, and only a few that have particular significance are likely to be named.

==See also==
* [[Form (zoology)]]
* [[Forma specialis]], an informal rank used for a parasitic form adapted to a particular host
*[[Trinomial nomenclature]]
*[[Variety (botany)]]
*[[Subvariety (botany)|Subvariety]]
*[[Plant variety (disambiguation)]]
*[[Cultivar]]
*[[Hybrid (biology)]]
*[[Race (biology)]]

==References==
{{reflist}}

{{Taxonomic ranks}}

{{Clear}}

{{DEFAULTSORT:Form (Botany)}}
[[Category:Botanical nomenclature|Form]]
[[Category:Forma taxa]]