Name and Classification

Species Name

At the top of each record is the species' scientific name. In most cases (with the exception of viruses), this is written as:

Genus species


Genus species Authority

Note: the words used to describe the parts of a scientific name vary depending on the type of organism. Generally, the first part of the name (which states the genus) is referred to as the “generic name”. For plants, fungi, and related taxa, the second part of the name (which refers to the species component) is called the “specific epithet”. For animals, the second part of the name is usually referred to as the “specific name”. When describing the format for a scientific name, Mass Nature refers to the first part of a scientific name as the “genus” or “genus name” and the second part of the name as the “species” or “species name”. Be aware that the terms “species” and “species name” are normally used to refer to the full scientific name (genus + specific epithet or specific name).

The scientific name is written in Latin and is italicized. The first letter of the genus name is capitalized, while the species name (specific epithet or specific name) is written in all lowercase letters.

The authority refers to the name of the author(s) who first named the species in a publication. For some taxa the date that the species was named may also be indicated.

Naming conventions vary somewhat depending on the type of organism, as summarized below.

Scientific names for plants, fungi, algae, cyanobacteria, chytrids, oomycetes, slime molds, and photosynthetic protists with their taxonomically related non-photosynthetic groups (but excluding Microsporidia):

  • The naming convention used for these organisms follows the International Code for Nomenclature (ICN) for algae, fungi and plants:
  • For these taxa, the authority is normally abbreviated, for example, Acer rubrum L.
  • In the example above, L. is an abbreviation for Carl Linnaeus (Carl von Linné). Linnaeus was considered the “Father of Taxonomy”; he created the binomial system for naming organisms (i.e., the genus name followed by the species name [specific name/specific epithet]), and he named over 12,000 organisms over the course of his career (Linnean Society of London []).
  • Some authority names include initials that preceed the surname. The initials are used so that it is possible to distinguish between authors with the same last name. For example, J.R. Abbott and L.K. Abbott. In some cases, a lowercase f. appears at the end of an authority name. The f. stands for filius, which means "son" in Latin. This means that the author is the son of another author. So, for example, the abbreviated authority name L.f. refers to the son of Carl Linnaeus (who was also named Carl Linnaeus). Hook.f. refers to Joseph Dalton Hooker, who was the son of William Jackson Hooker (whose authority name is abbreviated Hook.).
  • You can look up the abbreviation for a particular authority (or find out which authority an abbreviation refers to) using the International Plant Names Index (IPNI) website:
  • For some taxa, the authority consists of an abbreviation in parentheses followed by an abbreviation that is not in parentheses. For example, Schizachyrium scoparium (Michx.) Nash.
  • The name in parentheses refers to the original author who named the plant (in this case André Michaux, abbreviated as Michx.). The parentheses indicates that formerly the plant was assigned a different genus name by the original author (or the rank of the taxon was different) (In this case the genus name was formerly Andropogon and the scientific name was formerly written as Andropogon scoparius Michx.). The abbreviation following the parentheses refers to the author who revised the scientific name (in this case George Valentine Nash). You’ll notice that when the genus name was changed the ending on the second part of the name changed (from scoparius to scoparium). If the second part of the binomial is an adjective, as it is in this case, then the adjective must agree in gender with the genus name (i.e., written as feminine, masculine, or neuter). For example, Andropogon is masculine so the adjective in this case ends in –us (i.e., scoparius). Schizachyrium is neuter so the adjective ends in –um (scoparium).
  • When “ex” is used in the authority name, it indicates that the scientific name first given to the organism was not validly published. However, subsequently, the original scientific name was validly published either by a different author or the same author. The name immediately following the "ex" is that of the author who validly published the scientific name. For example, Boechera laevigata (Muhl. ex Willd.) Al-Shehbaz.
  • In the example above, the species was first named Arabis laevigata by Muhl. (Gotthilf Henry Ernest Muhlenberg) but the name was not validly published. The name Arabis laevigata was subsequently validly published by Willd. (Carl Ludwig Willdenow). Then the scientific name was revised (the genus name was changed to Boechera) by Al-Shehbaz (Ihsan Ali Al-Shehbaz).
  • When the name proceeding the “ex” is a lowercase “hort.”, this means that the plant name is of garden origin (i.e., it was widely used in horticulture and gardening but was never properly published). The abbreviation “hort.” stands for hortulanorum, which means “of gardeners”. An example is Prunus susquehanae hort. ex Willd.
  • An “x” is used before the second part of the binomial if a taxon is a hybrid. For example: Lonicera xbella is a hybrid resulting from a cross between Lonicera morowii and Lonicera tatarica.
  • An “x” that is used before the genus name indicates that the hybridization occurred between species from two different genera. For example: xElyhordeum macounii is the result of a cross between Elymus trachycaulus and Hordeum jubatum.
  • Sometimes taxonomic ranks below the level of species are used. These ranks include subspecies (abbreviated subsp.), variety (abbreviated var.), and form (forma) (abbreviated f.). A subspecies is immediately below the rank of species, while a variety is below the rank of subspecies, and a form is below the rank of variety.
  • The rank of subspecies is used to distinguish between groups of the same species that are (or were in the recent past) genetically/geographically isolated from each other. For example, Achillea millefolium subsp. lanulosa is considered to be the subspecies of yarrow that is native to New England, whereas Achillea millefolium subsp. millefolium is believed to be native to Eurasia (Go Botany, 2017 []).
  • The rank of variety is used to distinguish between groups of the same species or of the same subspecies, which differ based on minor but consistently observed characteristics. For example, Cypripedium parviflorum var. pubescens, C. parviflorum var. parviflorum, and C. parviflorum var. makasin are all considered to be varieties of Cypripedium parviflorum that occur in New England.
  • The rank of form is infrequently used. Different forms of a variety, subspecies or species are distinguished based on characteristics that tend to be trivial and in many cases impermanent. An example is the white-colored form of the pink lady slipper: Cypripedium acaule f. albiflorum.

Scientific names for animals, protozoans and Microsporidia:

  • Scientific names for animals, protozoans and Microsporidia follow the International Code of Zoological Nomenclature (ICZN) ( With animals, the name of the author doesn't form part of the taxon name and its citation is optional; although it is recommended that the original author and date that the scientific name was published are cited at least once in a publication concerning the particular taxon.
  • The name of the author/authority is not normally abbreviated. For example, Apis mellifera Linnaeus, 1758
  • If the genus name is changed, then the scientific name is written with the original author’s name in parentheses, as follows: Genus species (original author's name) or Genus species (original author's name, date the species was originally named). For example, Odocoileus virginianus (Zimmermann, 1780).
  • Note the author who revised the name and the date that the name was revised are not indicated.
  • Scientific names for subspecies are written as follows: Genus species subspecies. For example, the subspecies of Melissa Blue butterfly that occurs in New England (known as the Karner Blue) is Plebejus melissa samuelis. The subspecies of Melissa Blue that is found in the central and western U.S. is Plebejus melissa melissa.
  • Note, no abbreviation is used to denote a subspecies. This is because scientific names for animals, protozoans and Microsporidia generally do not include taxonomic ranks below the level of subspecies. Therefore, whenever you see a trinomial scientific name for these types of organisms, the third name will always refer to the subspecies.

Scientific names for archaea and bacteria (excluding cyanobacteria):

  • Scientific names for bacteria and archaea are written in accordance with the International Code of Nomenclature of Bacteria (ICNB) (
  • According to the ICNB, the name of a taxon should be cited in the following format: Genus species author year. With the author referring to the name of the author who first published the scientific name, and the year referring to the original year of publication. For example: Actinomyces bovis Harz 1877.
  • If a name is revised, so that the original genus name is changed, then the name of the original author is written in parentheses, preferably with the original publication date. Next, the name of the author who proposed the revision and the year of publication of the proposed change is provided. The following example is given by ICNB: Bacillus polymyxa (Prazmowski 1880) Macé 1889.

Scientific names for viruses:

  • Names for viruses are written according to the International Committee on Taxonomy of Viruses (ICTV)'s International Code of Virus Classification and Nomenclature (
  • According to the ICTV “Virus taxon nomenclature is recognized as an exception in the proposed International Code of Bionomenclature (Biocode).
  • Viruses are classified into the following taxonomic levels (although all levels in the taxonomic hierarchy need not be used):
    • Order
    • Family
    • (Subfamily)
    • Genus
    • Species
  • Viruses are primarily classified into the taxonomic level of species. The species name alone provides an unambiguous reference to the species. Typically the species name includes the name of the host and the word “virus” but it must be distinct and cannot consist solely of these components. Species names usually contain more than one word, they are written in italics, and the first letter of the first word is capitalized (other words are not capitalized unless they are proper nouns). For example, Tobacco mosaic virus.
  • Virus genera, subfamilies, families and orders are also printed in italics and the first letters of the names are capitalized.
  • The genus name is a single word ending in -virus.
  • The subfamily name is a single word ending in -virinae.
  • The family name is a single word ending in -viridae.
  • The order name is a single word ending in -virales
  • An example of a virus and its associated species, genus, subfamily, family and order names is provided below:
    • Species: Escherichia virus K5
    • Genus: Sp6virus
    • Subfamily: Autographivirinae
    • Family: Podoviridae
    • Order: Caudovirales
  • Retrotransposons are considered to be viruses and are classified and named in the same way as viruses.
  • Viroids are classified and named in the same manner as viruses, except the species name ends in viroid (e.g., Potato spindle tuber viroid), the genus name ends in -viroid (e.g., Pospiviroid), the subfamily ends in -viroinae and the family name ends in -viroidae (e.g., Pospiviroidae).


This section lists any other scientific names used to refer to the species.

There may be more than one scientific name used for a species for reasons such as:

  • Someone named a species not realizing it was already named. Normally, the earliest validly published name is used. So a species name will be changed if an earlier published name is discovered.
  • New taxonomic data become available indicating that the species should be classified differently (e.g. a species may be moved to a different genus or family; or perhaps two species may get lumped into one or one species may get split into two).
  • Scientific experts may not agree on which name should be used because they disagree on how the species should be classified. So, depending on the reference source that you use, the species may be named differently. Some taxonomists are described as being lumpers, because they have a tendency to lump together into one species organisms that may have some differing morphological or genetic traits; on the opposite end of the spectrum are splitters, who have a tendency to split organisms into many species based on minor differences.

Some of the synonyms that are listed may be old names that are no longer in use by anyone. For example, Eastern White Pine was originally named Strobus strobus by Linnaeus. However, modern rules of botanical nomenclature (e.g., ICN) do not allow the same word to be used for both parts of the binomial scientific name. So this species is now (perhaps universally) referred to as Pinus strobus. (Incidentally, this rule does not apply to the naming of animals. With respect to animals, when a species' generic and specific names are identical to one another, it indicates that the species is considered to be the "type" species (representative member) for that genus.)

Many synonyms were obtained from the sources listed below. Synonyms were also identified based on name discrepancies encountered when looking up taxa on species lists for different states and when comparing species names among other references.


"Main Group", "Sublevel1", and "Sublevel2" are informal groupings used by Mass Nature.

Plants were classified into Family, Genus, and Species following Haines, 2011.

Animals were classified into the taxonomic ranks of Phylum, Class, Order, Family, Genus, and Species used by the Integrated Taxonomic Information System (ITIS) ( In cases where animal taxa were not listed in ITIS, classification information was obtained from (, Discover Life (, or NatureServe Explorer (

Ranks used for protoctists included Phylum or Division, Class, Order, Family, Genus, and Species. Classification/nomenclature for protoctists follows that of AlgaeBase ( for algae, MycoBank ( for mycetozoan slime molds, and World Register of Marine Species (WoRMS) ( for protoctists not listed in the latter two databases.

Fungi were classified into Division, Class, Order, Family, Genus, and Species, with classificaton and nomenclature following that of MycoBank (

References Hosted by Iowa State University Department of Entomology. URL:

Discover Life. URL:

Go Botany. Go Botany [2.5]. New England Wild Flower Society.URL:

Haines, A. 2011. New England Wildflower Society's Flora Novae Angliae. A Manual for the Identification of Native and Naturalized Higher Vascular Plants of New England. Yale University Press, New Haven, CT. 973 pages.

Integrated Taxonomic Information System (ITIS). Last updated May 5, 2017. URL:

International Association for Plant Taxonomy (IAPT). 2012. International Code of Nomenclature for algae, fungi, and plants (Melbourne Code). Adopted by the 18th International Botanical Congress Melbourne, Australia. July 2011. Regnum Vegetabile 154. Koeltz Scientific Books. Available from:

International Commission on Zoological Nomenclature (ICZN) 1999. International Code of Zoological Nomenclature. Fourth Edition. Adopted by the International Union of Biological Sciences. Published by the International Trust for Zoological Nomenclature 1999. Available from:

International Committee on Taxonomy of Viruses (ICTV). 2017. The International Code of Virus Classification and Nomenclature. April 2017. Available from:

International Plant Names Index (IPNI). Last updated 23 April 2015. URL:

Lapage, S.P. P.H.A. Sneath, E.F. Lessel, V.B.D. Skermann, H.P.R. Seeliger, and W.A. Clark (eds.) 1992. International Code of Nomenclature of Bacteria. Bacteriological Code, 1990 Revision. ASM Press, Washington, D.C. Available from:

The Linnean Society of London. Who was Linnaeus? URL:

NatureServe Explorer. An Online Encyclopedia of Life. Updated November 2016. URL:

The Plant List. 2013. Version 1.1. URL:

USDA Plants Database. U.S. Department of Agriculture. Natural Resources Conservation Service. URL:

Last edited: 19 Sept. 2017