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Names of Plants, Animals, and Microorganisms

The most familiar names of living and formerly living things are the common, or vernacular, names determined by popular usage, in which one organism may have several names (as mountain lion, cougar, and painter), different organisms may have the same name (as dolphin), and there may be variation in meaning or overlapping of the categories denoted by the names (as whale, dolphin, and porpoise).

In contrast, the scientific names of biological classification are governed by four highly prescriptive, internationally recognized codes of nomenclature for botany, zoology, bacteriology, and virology. The vocabularies of these nomenclatures have been developed and used by scientists for the purpose of identifying and indicating the relationships of plants, animals, and microorganisms. These systems of names classify each kind of organism into a hierarchy of groups – taxa – with each kind of organism having one – and only one – correct name and belonging to one – and only one – taxon at each level of classification in the hierarchy.

The taxonomic names of biological classification are used in this dictionary at entries that define common names of plants, animals, and microorganisms, as well as diseases of or products relating to plants, animals, or microorganisms that do not themselves have common names that qualify for entry here. Names from several different codes of nomenclature may appear in the same definition. Each is enclosed in parentheses, usually following an orienting noun:

Rocky Mountain spotted fever noun . . . : an acute disease that is characterized by chills, fever, prostration, pains in muscles and joints, and a red to purple eruption and that is caused by a rickettsia (Rickettsia rickettsii) usually transmitted by an ixodid tick and especially either the American dog tick or a wood tick (Dermacentor andersoni)

sand·fly fever . . . noun . . . : a disease . . . that is caused by any of several single-stranded RNA viruses (genus Phlebovirus of the family Bunyaviridae) transmitted by the bite of a sand fly (especially Phlebotomus papatasii) . . .

Within the parentheses the prescriptive principles of the relevant nomenclature hold, but as soon as the reader steps outside the parentheses the rules of general usage hold. For example, the genus name Apatosaurus for a group of large herbivorous dinosaurs is now the valid name in biological classification for the formerly accepted Brontosaurus. While apatosaurus is available as a common name, it has been slow in displacing brontosaurus in popular usage. So the main definition of the dinosaur is placed at the vocabulary entry for brontosaurus, while only a cross-reference in small capitals appears at apatosaurus. However, within the parenthetical identification, the genus name Apatosaurus appears first, with Brontosaurus listed second as a synonym:

apato·sau·rus . . . noun . . . : BRONTOSAURUS
bron·to·sau·rus . . . also bron·to·saur . . . noun . . . : any of a genus (Apatosaurus syn. Brontosaurus) of large sauropod dinosaurs of the Jurassic — called also apatosaurus

Taxonomic names are used in definitions in this dictionary to provide precise identifications through which defined terms may be pursued in technical writings. Because of their specialized nature, taxonomic names as such are not included as dictionary entries. However, many common names entered in this dictionary have been derived directly from genus names and other taxonomic names, often with little or no modification. In written text it is particularly important to distinguish between a common name and the taxonomic name from which it is derived. In contrast to the styling rules for taxonomic names (discussed below), common names (as "clostridium," "drosophila," and "enterovirus") are not usually capitalized or italicized, and common names derived from genus names can have a plural form even though genus names themselves are never pluralized.

The entries defining plants, animals, and microorganisms are usually oriented to higher taxa by common, vernacular terms within the definitions (as "alga" at seaweed, "thrush" at robin, and "picornaviruses" at enterovirus) or by technical adjectives (as "composite" at daisy and "oscine" at warbler).

When the vernacular name of a plant or animal is used to identify the vernacular name of the taxonomic family to which the plant or animal belongs, that information will be given in parentheses in the definition of the plant or animal, and definitions for other organisms within that family will refer to the vernacular family name:

²rose . . . noun . . . 1 a : any of a genus (Rosa of the family Rosaceae, the rose family) of usually prickly shrubs
ap·ple . . . noun, often attributive . . . 1 : the fleshy usually rounded red, yellow, or green edible pome fruit of a usually cultivated tree (genus Malus) of the rose family; also : an apple tree
¹squir·rel . . . noun . . . 1 : any of various small or medium-sized rodents (family Sciuridae, the squirrel family): as . . .
chip·munk . . . noun . . . : any of a genus (Tamias) of small striped North American and Asian rodents of the squirrel family

Linnaean Nomenclature of Plants, Animals, and Bacteria

The nomenclatural codes for botany, zoology, and bacteriology follow the binomial nomenclature of Carolus Linnaeus, who employed a New Latin vocabulary for the names of organisms and the names of ranks in the hierarchy of classification.

The fundamental taxon is the genus. It includes a group of closely related kinds of plants (as Prunus, which includes the wild and cultivated cherries, apricots, peaches, and almonds), a group of closely related kinds of animals (as Canis, which includes domestic dogs, coyotes, jackals, and wolves), or a group of closely related kinds of bacteria (as Streptococcus, which includes numerous pathogens of humans and domestic animals). The genus name is an italicized and capitalized singular noun.

The unique name of each kind of organism or species in the Linnaean systems is the binomial or species name, which consists of two parts: a genus name and an italicized lowercase word—the specific epithet—denoting the species. A trinomial is used to name a variety or a subspecies and consists of a binomial plus an italicized lowercase word denoting the variety or subspecies. For example, the cultivated cabbage (Brassica oleracea capita), the cauliflower (Brassica oleracea botrytis), and brussels sprouts (Brassica oleracea gemmifera) sprouts belong to the same species (Brassica oleracea) of cole.

The genus name in a binomial or trinomial may be abbreviated to its initial letter if it has previously been spelled out in full within the same text. In this dictionary, a genus name is abbreviated only when it is used more than once in senses not separated by a boldface sense number.

nas·tur·tium . . . noun . . . : any of a genus (Tropaeolum of the family Tropaeolaceae, the nasturtium family) of herbs of Central and South America with showy spurred flowers and pungent edible seeds and leaves ; especially : either of two widely cultivated ornamentals (T. majus and T. minus)

Names of taxa higher than the genus (as family, order, and class) are capitalized plural nouns that are often used with singular verbs and that are not abbreviated in normal use. They are not italicized.

¹bee·tle . . . noun . . . 1 : any of an order (Coleoptera) of insect . . .

A genus name in good standing cannot be the name of two different groups of animals, groups of plants, or groups of bacteria. At least one of the applications must be invalid. However, since the nomenclatural codes are independent, an animal genus and a plant genus, for example, may validly receive the same name. Thus, a number of cabbage butterflies (as Pieris rapae) are placed in a genus of animals that has the same name as the plant genus to which the Japanese andromeda (Pieris japonica) belongs. Although no two higher taxa of plants or of bacteria are permitted to have the same name, the rules of zoological nomenclature do not apply to taxa above the family, and so, for example, it is possible for widely separated groups of animals to be placed in families or orders with identical taxonomic names.

Sometimes two or more different New Latin names can be found used in current literature for the same organism or group. This happens when old monographs and field guides are kept in print after name changes occur, when there are legitimate differences of opinion about the validity of the names, and when the rules of priority are not applied. To help the reader in recognizing an organism or group, some entries in this dictionary give two taxonomic names connected by "syn." (for "synonym"):

wa·ter·mel·on . . . noun . . . 1 : a large oblong or roundish fruit with a hard green or white rind . . .
2 : a widely cultivated African vine (Citrullus lanatus syn. C. vulgaris) of the gourd family that bears watermelons

Virus Nomenclature

The system of naming viruses evolved in a series of reports by a committee of the International Union of Microbiological Societies. The report published in 2000 with the title Virus Taxonomy: Seventh Report of the International Committee on Taxonomy of Viruses is the one followed in this dictionary. The code of nomenclature developed there is independent of the three Linnaean systems governing the taxonomy of plants, animals, and bacteria and differs in the way names are constructed and written.

Except as noted below, the names for species, genera, and families of viruses used in this dictionary are those that are recognized by the International Committee on Taxonomy of Viruses. Such names appear in italics and are preceded by the name of the taxon ("species," "genus," or "family") in roman before the italicized name.

The name of a species consists of an italicized phrase in which the first word is capitalized, other words are lowercase unless derived from a proper name, and the last word is virus.

The name of a genus is usually a single capitalized word ending in -virus.

The name of a family is a single capitalized word ending in -viridae.

small·pox . . . noun . . . : an acute contagious febrile disease of humans that is caused by a poxvirus (species Variola virus of the genus Orthopoxvirus) . . .

The name of the family in this case can be found at the entry for poxvirus:

pox·vi·rus . . . noun . . . : any of a family (Poxviridae) of brick-shaped or ovoid double-stranded DNA viruses . . .

Unlike the Linnaean codes, virus nomenclature does not have in place a protocol for handling synonyms, names that were once in good standing but have been replaced by others. Several names (as family Myxoviridae and family Papovaviridae) that were in good standing in the Sixth Report of the International Committee on Virus Taxonomy are not found in any of the indices of the Seventh Report. At best a word or two of explanation is offered in the taxa replacing them. In order to provide continuity, common names for members of defunct taxa are retained in this dictionary when those names are still in common use:

pa·po·va·vi·rus . . . noun : any of a former family (Papovaviridae) of double-stranded DNA viruses associated with various neoplasms of mammals that included the papillomaviruses and the polyomaviruses

The names of the two families to which the papovaviruses are now assigned can be found at the definitions of papillomavirus and polyomavirus.