Botanical nomenclature - AbsoluteAstronomy.com

Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy

Alpha taxonomy

Alpha taxonomy is the discipline concerned with finding, describing and naming species of living or fossil organisms. This field is supported by institutions holding collections of these organisms, with relevant data, carefully curated: such institutes include natural history museums, herbaria and...

. Plant taxonomy is concerned with grouping and classifying plants; botanical nomenclature then provides names for the results of this process. The starting point for modern botanical nomenclature is Linnaeus' Species Plantarum of 1753. Botanical nomenclature is governed by the International Code of Nomenclature for algae, fungi, and plants

International Code of Nomenclature for algae, fungi, and plants

The International Code of Nomenclature for algae, fungi, and plants is the set of rules and recommendations dealing with the formal botanical names that are given to plants, fungi and a few other groups of organisms, all those "traditionally treated as plants"., Preamble, para...

(ICN), which replaces the International Code of Botanical Nomenclature (ICBN).

History and scope

Botanical nomenclature has a long history, going back to the period when Latin was the scientific language throughout Europe, and perhaps further back to Theophrastus

Theophrastus

Theophrastus , a Greek native of Eresos in Lesbos, was the successor to Aristotle in the Peripatetic school. He came to Athens at a young age, and initially studied in Plato's school. After Plato's death he attached himself to Aristotle. Aristotle bequeathed to Theophrastus his writings, and...

. A key event was Linnaeus’ adoption of binomial names

Binomial nomenclature

Binomial 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 grammatical forms, although they can be based on words from other languages...

for plant species in his Species Plantarum (1753). Every plant species is given a name that remains the same no matter what other species were placed in the genus, and this separates taxonomy

Alpha taxonomy

from nomenclature. These species names of Linnaeus together with names for other ranks (such as family, class, order, variety), can serve to express a great many taxonomic viewpoints.

In the nineteenth century it became increasingly clear that there was a need for rules to govern scientific nomenclature, and initiatives were taken to produce a body of laws. These were published in successively more sophisticated editions. For plants the key dates are 1867 (lois de Candolle), 1906 (International Rules of Botanical Nomenclature, 'Vienna Rules') and 1952 (International Code of Botanical Nomenclature, 'Stockholm Code). The most recent is the Vienna Code, adopted in 2005.

Another development was the insight into the delimitation of the concept of 'plant'. Linnaeus held a much wider view of what a plant is than is acceptable today. Gradually more and more groups of organisms are being recognised as being independent of plants. Nevertheless the formal names of most of these organisms are governed by the (ICN), even today. A separate Code was adopted to govern the nomenclature of Bacteria, the ICNB.

All formal botanical names are governed by the ICN, and within the limits set by that code there is another set of rules, the International Code of Nomenclature for Cultivated Plants (ICNCP)

International Code of Nomenclature for Cultivated Plants

The International Code of Nomenclature for Cultivated Plants regulates the names of cultigens...

. This latter code applies to plant cultivar

Cultivar

A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...

s, that have been deliberately altered or selected by humans (see cultigen

Cultigen

A cultigen is a plant that has been deliberately altered or selected by humans; it is the result of artificial selection. These "man-made" or anthropogenic plants are, for the most part, plants of commerce that are used in horticulture, agriculture and forestry...

) and require separate recognition.

Relationship to taxonomy

Botanical nomenclature is closely linked to plant taxonomy, and botanical nomenclature serves plant taxonomy, but nevertheless botanical nomenclature is separate from plant taxonomy. Botanical nomenclature is merely the body of rules prescribing which name applies to that taxon (see correct name

Correct name (botany)

In botany, the correct name according to the International Code of Botanical Nomenclature is the one and only botanical name that is to be used for a particular taxon, when that taxon has a particular circumscription, position and rank. Determining whether a name is correct is a complex procedure...

) and if a new name may (or must) be coined.

Plant taxonomy

Alpha taxonomy

is an empirical science, a science that determines what constitutes a particular taxon

Taxon

|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

(taxonomic grouping, plural: taxa): e.g. "What plants belong to this species?" and "What species belong to this genus?". The definition of the limits of a taxon is called its 'circumscription

Circumscription (taxonomy)

In taxonomy, circumscription is the definition of the limits of a taxonomic group of organisms. One goal of taxonomy is to achieve a stable circumscription for every taxonomic group. Achieving stability can be simple or difficult....

'. For a particular taxon, if two taxonomists agree exactly on its circumscription, rank and position (i.e. the higher rank in which it is included) then there is only one name which can apply under the ICN. Where they differ in opinion on any of these issues, one and the same plant may be placed in taxa with different names. As an example, consider Siehe's Glory-of-the-Snow, Chionodoxa siehei

Chionodoxa siehei

Chionodoxa siehei or Siehe's Glory-of-the-Snow is a bulbous perennial from west Turkey flowering in early spring. After flowering, it goes into dormancy until the next spring. It seeds readily to form colonies.-Description:...

Taxonomists can disagree as to whether two groups of plants are sufficiently distinct to be put into one species or not. Thus Chionodoxa siehei
Chionodoxa siehei
Chionodoxa siehei or Siehe's Glory-of-the-Snow is a bulbous perennial from west Turkey flowering in early spring. After flowering, it goes into dormancy until the next spring. It seeds readily to form colonies.-Description:...

and Chionodoxa forbesii
Chionodoxa forbesii
Chionodoxa forbesii or Forbes' Glory-of-the-snow is a bulbous perennial from south-west Turkey flowering in early spring. After flowering, it goes into dormancy until the next spring....

have been treated as a single species by some taxonomists or as two species by others. If treated as one species, the earlier published name must be used, so plants previously called Chionodoxa siehei become Chionodoxa forbesii.

Taxonomists can disagree as to whether two genera are sufficiently distinct to be kept separate or not. While agreeing that the genus Chionodoxa
Chionodoxa
Chionodoxa ' is a small genus of bulbous perennials in the family Asparagaceae, subfamily Scilloideae. The genus is endemic to the eastern Mediterranean region, specifically Crete, Cyprus and Turkey. The blue, white or pink flowers appear early in the year making them valuable garden ornamentals...

is closely related to the genus Scilla
Scilla
Scilla is a genus of about 50 bulb-forming perennial herbs in the family Asparagaceae, subfamily Scilloideae, native to woodlands, subalpine meadows, and seashores throughout Europe and Asia...

, nevertheless the bulb expert Brian Mathew considers that their differences warrant maintaining separate genera. Others disagree, in which case they will call Chionodoxa siehei, for example, Scilla siehei. The earliest published genus name must be used when genera are merged;x in this case Scilla predates Chionodoxa.

Taxonomists can disagree as to the limits of families. When the Angiosperm Phylogeny Group
Angiosperm Phylogeny Group
The Angiosperm Phylogeny Group, or APG, refers to an informal international group of systematic botanists who came together to try to establish a consensus on the taxonomy of flowering plants that would reflect new knowledge about plant relationships discovered through phylogenetic studies., three...

(APG) first published its classification of the flowering plants in 1998, Chionodoxa siehei would have been placed in the family Hyacinthaceae, which was one of the families which was then recognized. In the 2009 revision of their classification, the APG no longer recognize the Hyacinthaceae as a separate family, merging it into a greatly enlarged family Asparagaceae
Asparagaceae
Asparagaceae is the botanical name of a family of flowering plants, placed in the order Asparagales of the monocots.In earlier classification systems, the species involved were often treated as belonging to the family Liliaceae...

. Thus Chionodoxa siehei moves from the Hyacinthaceae to the Asparagaceae.

Taxonomists can disagree as to the rank of a taxon. Rather than allow the Hyacinthaceae to disappear altogether, Chase et al. suggested that it be treated as a subfamily within the Asparagaceae. The ICN requires family names to end with "-aceae" and subfamily names to end with "-oideae". Thus a possible name for the Hyacinthaceae when treated as a subfamily would be 'Hyacinthoideae'. However, the name Scilloideae had already been published in 1835 as the name for a subfamily containing the genus Scilla, so this name has priority and must be used. Hence for those taxonomists who accept that there should be a subfamily for Scilla and related genera, and accept the APG system of 2009, Chionodoxa siehei is placed in the subfamily Scilloideae of the family Asparagaceae. However, a taxonomist is perfectly free to continue to argue that Hyacinthaceae should be maintained as a separate family from the other families which were merged into the Asparagaceae.

In summary, if a plant has different names or is placed in differently named taxa:

If the confusion is purely nomenclatural, i.e. it concerns what to call a taxon which has the same circumscription, rank and position, the ICN provides rules to settle the differences, typically by prescribing that the earliest published name must be used, although names can be conserved.
If the confusion is taxonomic, i.e. taxonomists differ in opinion on the circumscription, rank or position of taxa, then only more scientific research can settle the differences.

History and scope

Relationship to taxonomy

See also