Family (biology)

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Family (biology) LifeDomainKingdomPhylumClassOrderFamilyGenusSpecies
The hierarchy of biological classification's eight major taxonomic ranks. An order contains one or more families. Intermediate minor rankings are not shown.

Family (Latin : familia, plural familiae) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy; it is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as being the "walnut family".


What belongs to a family—or if a described family should be recognized at all—are proposed and determined by practicing taxonomists. There are no hard rules for describing or recognizing a family. Taxonomists often take different positions about descriptions, and there may be no broad consensus across the scientific community for some time. The publishing of new data and opinions often enables adjustments and consensus.


The naming of families is codified by various international bodies using the following suffixes:


The taxonomic term familia was first used by French botanist Pierre Magnol in his Prodromus historiae generalis plantarum, in quo familiae plantarum per tabulas disponuntur (1689) where he called the seventy-six groups of plants he recognised in his tables families (familiae). The concept of rank at that time was not yet settled, and in the preface to the Prodromus Magnol spoke of uniting his families into larger genera, which is far from how the term is used today.

Carolus Linnaeus used the word familia in his Philosophia botanica (1751) to denote major groups of plants: trees, herbs, ferns, palms, and so on. He used this term only in the morphological section of the book, discussing the vegetative and generative organs of plants.

Subsequently, in French botanical publications, from Michel Adanson's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille was used as a French equivalent of the Latin ordo (or ordo naturalis ).

In zoology, the family as a rank intermediate between order and genus was introduced by Pierre André Latreille in his Précis des caractères génériques des insectes, disposés dans un ordre naturel (1796). He used families (some of them were not named) in some but not in all his orders of "insects" (which then included all arthropods).

In nineteenth-century works such as the Prodromus of Augustin Pyramus de Candolle and the Genera Plantarum of George Bentham and Joseph Dalton Hooker this word ordo was used for what now is given the rank of family.


Families can be used for evolutionary, palaeontological and genetic studies because they are more stable than lower taxonomic levels such as genera and species. [4] [5]

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Linnaean taxonomy A rank based classification system for organisms

Linnaean taxonomy can mean either of two related concepts:

  1. the particular form of biological classification (taxonomy) set up by Carl Linnaeus, as set forth in his Systema Naturae (1735) and subsequent works. In the taxonomy of Linnaeus there are three kingdoms, divided into classes, and they, in turn, into orders, genera, and species, with an additional rank lower than species.
  2. a term for rank-based classification of organisms, in general. That is, taxonomy in the traditional sense of the word: rank-based scientific classification. This term is especially used as opposed to cladistic systematics, which groups organisms into clades. It is attributed to Linnaeus, although he neither invented the concept of ranked classification nor gave it its present form. In fact, it does not have an exact present form, as "Linnaean taxonomy" as such does not really exist: it is a collective (abstracting) term for what actually are several separate fields, which use similar approaches.
Taxonomy (biology) Science of naming, defining and classifying organisms

In biology, taxonomy is the science of naming, defining (circumscribing) and classifying groups of biological organisms on the basis of shared characteristics. Organisms are grouped together into taxa and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a super-group of higher rank, thus creating a taxonomic hierarchy. The principal ranks in modern use are domain, kingdom, phylum, class, order, family, genus, and species. The Swedish botanist Carl Linnaeus is regarded as the founder of the current system of taxonomy, as he developed a system known as Linnaean taxonomy for categorizing organisms and binomial nomenclature for naming organisms.

A genus is a taxonomic rank used in the biological classification of living and fossil organisms, as well as viruses, in biology. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus.

In biological classification, the order is

  1. a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family. An immediately higher rank, superorder, may be added directly above order, while suborder would be a lower rank.
  2. a taxonomic unit, a taxon, in that rank. In that case the plural is orders.
Taxon Group of one or more populations of an organism or organisms which have distinguishing characteristics in common

In biology, a taxon is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping.

Geraniales order of plants

Geraniales are a small order of flowering plants, included within the rosid subclade of eudicots. The largest family in the order is Geraniaceae with over 800 species. In addition, the order includes the smaller Francoaceae with about 40 species. Most Geraniales are herbaceous, but there are also shrubs and small trees.

Pierre Magnol French botanist (1638-1715)

Pierre Magnol was a French botanist. He was born in the city of Montpellier, where he lived and worked for most of his life. He became Professor of Botany and Director of the Royal Botanic Garden of Montpellier and held a seat in the Académie Royale des Sciences de Paris for a short while. He was one of the innovators who devised the botanical scheme of classification. He was the first to publish the concept of plant families as they are understood today, a natural classification of groups of plants that have features in common.

Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy. 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 (ICN), which replaces the International Code of Botanical Nomenclature (ICBN). Fossil plants are also covered by the code of nomenclature.

Nomenclature codes or codes of nomenclature are the various rulebooks that govern biological taxonomic nomenclature, each in their own broad field of organisms. To an end-user who only deals with names of species, with some awareness that species are assignable to families, it may not be noticeable that there is more than one code, but beyond this basic level these are rather different in the way they work.

Descriptive botanical names are scientific names of groups of plants that are irregular, not being derived systematically from the name of a type genus. They may describe some characteristics of the group in general or may be a name already in existence before regularised scientific nomenclature.

In botanical nomenclature, author citation is the way of citing the person or group of people who validly published a botanical name, i.e. who first published the name while fulfilling the formal requirements as specified by the International Code of Nomenclature for algae, fungi, and plants (ICN). In cases where a species is no longer in its original generic placement, both the authority for the original genus placement and that for the new combination are given.

In botany, the phrase ordo naturalis, "natural order", was once used for what today is a family. Its origins lie with Carl Linnaeus who used the word when he referred to natural groups of plants in his lesser-known work, particularly Philosophia Botanica. In his more famous works the Systema Naturae and the Species Plantarum, plants were arranged according to his artificial "Sexual system", and Linnaeus used the word "ordo" for an artificial unit. In those works, only genera and species were "real" taxa.

Lilianae superorder of plants

Lilianae is a botanical name for a superorder of flowering plants. Such a superorder of necessity includes the type family Liliaceae. Terminations at the rank of superorder are not standardized by the International Code of Nomenclature for algae, fungi, and plants (ICN), although the suffix -anae has been proposed.

James L. Reveal American botanist

James Lauritz Reveal was a U.S. botanist best known for his contributions to the genus Eriogonum and for his work on suprageneric names. His website, at, also presents material on plant taxonomy including the Reveal system. He published extensively on North American flora, was a member of the Angiosperm Phylogeny Group, and was one of the authors of the APG II and APG III classifications.

A conserved name or nomen conservandum is a scientific name that has specific nomenclatural protection. That is, the name is retained, even though it violates one or more rules which would otherwise prevent it from being legitimate. Nomen conservandum is a Latin term, meaning "a name to be conserved". The terms are often used interchangeably, such as by the International Code of Nomenclature for Algae, Fungi, and Plants (ICN), while the International Code of Zoological Nomenclature favours the term "conserved name".

<i>Prodromus Systematis Naturalis Regni Vegetabilis</i>

Prodromus Systematis Naturalis Regni Vegetabilis (1824–1873), also known by its standard botanical abbreviation Prodr. (DC.), is a 17-volume treatise on botany initiated by Augustin Pyramus de Candolle. De Candolle intended it as a summary of all known seed plants, encompassing taxonomy, ecology, evolution and biogeography. He authored seven volumes between 1824 and 1839, but died in 1841. His son, Alphonse de Candolle, then took up the work, editing a further ten volumes, with contributions from a range of authors. Volume 17 was published in October 1873. The fourth and final part of the index came out in 1874. The Prodromus remained incomplete, dealing only with dicotyledons.

Taxonomic rank Level in a taxonomic hierarchy

In biological classification, taxonomic rank is the relative level of a group of organisms in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, order, class, phylum, kingdom, domain, etc.

This is a list of terms and symbols used in scientific names for organisms, and in describing the names. For proper parts of the names themselves, see List of Latin and Greek words commonly used in systematic names. Note that many of the abbreviations are used with or without a stop.

Burmanniales order of plants

BurmannialesMart. was an order of monocotyledons, subsequently discontinued.


  1. Barnhart 1895.
  2. ICN 2012, Section 2. Names of families and subfamilies, tribes and subtribes Article 18.
  3. International Commission on Zoological Nomenclature (1999). "Article 29.2. Suffixes for family-group names". International Code of Zoological Nomenclature (Fourth ed.). International Trust for Zoological Nomenclature, XXIX. p. 306. Archived from the original on 9 November 2004.
  4. Sarda Sahney, Michael J. Benton & Paul A. Ferry (2010). "Links between global taxonomic diversity, ecological diversity and the expansion of vertebrates on land". Biology Letters . 6 (4): 544–547. doi:10.1098/rsbl.2009.1024. PMC   2936204 . PMID   20106856.
  5. Sarda Sahney & Michael J. Benton (2008). "Recovery from the most profound mass extinction of all time". Proceedings of the Royal Society B: Biological Sciences. 275 (1636): 759–765. doi:10.1098/rspb.2007.1370. PMC   2596898 . PMID   18198148.