In
botanical nomenclature
Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy (biology), taxonomy. Plant taxonomy is concerned with grouping and classifying plants; Botany, botanical nomenclature then provides na ...
, a ''form'' (''forma'', plural ''formae'') is one of the "secondary"
taxonomic rank
In biology, taxonomic rank (which some authors prefer to call nomenclatural rank because ranking is part of nomenclature rather than taxonomy proper, according to some definitions of these terms) is the relative or absolute level of a group of or ...
s, below that of
variety
Variety may refer to:
Arts and entertainment Entertainment formats
* Variety (radio)
* Variety show, in theater and television
Films
* ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont
* ''Variety'' (1935 film), ...
, which in turn is below that of species; it is an
infraspecific taxon
In botany, an infraspecific name is the scientific name for any taxon below the rank of species, i.e. an infraspecific taxon or infraspecies. The scientific names of botanical taxa are regulated by the ''International Code of Nomenclature for al ...
. 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
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
name, a
specific epithet
In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...
, 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
''Crataegus aestivalis'', known as the eastern mayhaw, is a shrub or small tree of the southeastern United States that grows in low-lying or wet areas from eastern Alabama to central Florida and Virginia. It is one of several species of hawthor ...
'' (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
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
).
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
In botany, apomixis is asexual development of seed or embryo without fertilization. However, other definitions include replacement of the seed by a plantlet or replacement of the flower by bulbils.
Apomictically produced offspring are geneti ...
. 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)
In zoology, the word "form" or "''forma''" (literally Latin for ''form'') is a strictly informal term that is sometimes used to describe organisms. Under the ''International Code of Zoological Nomenclature'' the term has no standing (it is not ac ...
*
Forma specialis
''Forma specialis'' (plural: ''formae speciales''), abbreviated f. sp. (plural ff. spp.) without italics, is an informal taxonomic grouping allowed by the International Code of Nomenclature for algae, fungi, and plants, that is applied to a para ...
, an informal rank used for a parasitic form adapted to a particular host
*
Trinomial nomenclature
In biology, trinomial nomenclature is the system of names for taxa below the rank of species. These names have three parts. The usage is different in zoology and botany.
In zoology
In zoological nomenclature, a trinomen (), trinominal name, or ...
*
Variety (botany)
In botanical nomenclature, variety (abbreviated var.; in ) is a taxonomic rank below that of species and subspecies, but above that of form. As such, it gets a three-part infraspecific name. It is sometimes recommended that the subspecies r ...
*
Subvariety Subvariety may refer to:
* Subvariety (botany)
* Subvariety (algebraic geometry)
* Variety (universal algebra)
In universal algebra, a variety of algebras or equational class is the class of all algebraic structures of a given signature satis ...
*
Plant variety (disambiguation) Plant variety may refer to:
*Variety (botany), a formal rank, in taxonomic nomenclature, below subspecies
*Colloquially (and historically):
**Cultivar, especially of grapes and rice
**Hybrid (biology), more generally
**Any form (botany) (a taxonomic ...
*
Cultivar
A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...
*
Hybrid (biology)
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different varieties, subspecies, species or genera through sexual reproduction. Generally, it means that each cell has genetic material from two ...
*
Race (biology)
In Taxonomy (biology), biological taxonomy, race is an informal group (taxonomy), informal Taxonomic rank, rank in the taxonomic hierarchy for which various definitions exist. Sometimes it is used to denote a level below that of subspecies, whi ...
References
{{DEFAULTSORT:Form (Botany)
Form
Form is the shape, visual appearance, or configuration of an object. In a wider sense, the form is the way something happens.
Form may also refer to:
*Form (document), a document (printed or electronic) with spaces in which to write or enter dat ...
Forma taxa