Overview
In botanical classification, a variety denotes an infraspecific rank used to recognize a naturally occurring group of plants within a species that consistently differs in one or more morphological traits. As a formal taxon, a variety is ranked below species and subspecies and above form in many classification systems. The rank is commonly abbreviated as "var." and is part of scientific plant nomenclature governed by the International Code of Nomenclature for algae, fungi, and plants (ICN).
Naming and examples
Varieties are named using a trinomial combination: the genus name, the species epithet, and the variety epithet (for example, Genus species var. variety). This three-part name indicates the hierarchical relationship to the species while recording the distinguishing epithet. Typical published examples include:
- Acer palmatum var. atropurpureum — a purple-leaved form of Japanese maple
- Abies lasiocarpa var. arizonica — a regional corkbark fir variety
- Hosta undulata var. undulata — a variant within plantain lilies
The use of the variety epithet communicates that the difference is persistent in nature and recognized by taxonomists; however, authors may differ in how they apply the rank.
Characteristics and distinctions
Varieties are generally distinguished from related ranks by the scope and permanence of their differences. Common distinctions include:
- Compared with a subspecies: varieties often represent smaller or less geographically separated differences; subspecies usually imply broader, often geographically delimited variation.
- Compared with a form: a form (f.) normally denotes very minor differences such as flower color or leaf variegation, while a variety shows more substantial or multiple traits.
- Compared with a cultivar: horticultural cultivars are human-selected and named under the International Code of Nomenclature for Cultivated Plants; they are written differently (often in single quotes) and are not the same as botanical varieties that arise and persist in the wild.
Importantly, different varieties of the same species usually interbreed where their ranges overlap; varieties are not reproductively isolated to the extent of separate species.
History and taxonomic practice
The use of the variety rank has evolved with botanical practice. Historically, authors introduced varieties to record noticeable, stable deviations within widely distributed species. Modern taxonomists may apply the rank differently: some prefer to recognize clear geographic or ecological subdivisions as subspecies, others as varieties, and some may choose not to use infraspecific ranks at all. Taxonomic revision frequently changes the status of a taxon—varieties can be elevated to subspecies or species, or they can be synonymized with the typical species after further study.
Importance, uses and conservation
Recognizing varieties has practical value for ecology, conservation, and horticulture. Documenting intraspecific diversity helps target conservation measures for locally distinct populations and preserves genetic variation important for adaptation. In horticulture, knowledge of botanical varieties complements cultivar naming and assists gardeners and breeders in understanding the origin and natural variation of plants. Because the decision to recognize a variety relies on morphological consistency and taxonomic judgment, botanical literature and herbarium specimens remain essential resources for accurate identification.
For general context about the rank and related terms see references to species and subspecies, and consult taxonomic treatments for particular plant groups when precise application of the variety rank is required.