Plant taxonomy

Last updated

Plant taxonomy is the science that finds, identifies, describes, classifies, and names plants. It is one of the main branches of taxonomy (the science that finds, describes, classifies, and names living things).


Plant taxonomy is closely allied to plant systematics, and there is no sharp boundary between the two. In practice, "plant systematics" involves relationships between plants and their evolution, especially at the higher levels, whereas "plant taxonomy" deals with the actual handling of plant specimens. The precise relationship between taxonomy and systematics, however, has changed along with the goals and methods employed.

Plant taxonomy is well known for being turbulent, and traditionally not having any close agreement on circumscription and placement of taxa. See the list of systems of plant taxonomy.


Classification systems serve the purpose of grouping organisms by characteristics common to each group. Plants are distinguished from animals by various traits: they have cell walls made of cellulose, polyploidy, and they exhibit sedentary growth. Where animals have to eat organic molecules, plants are able to change energy from light into organic energy by the process of photosynthesis. The basic unit of classification is species, a group able to breed amongst themselves and bearing mutual resemblance, a broader classification is the genus. Several genera make up a family, and several families an order. [1]

Plantae, the Plant Kingdom

The plant kingdom is divided according to the following:

Bryophyta MossesNo vascular system, distinctive vegetative structures, spores produced for reproduction require damp conditions for survival, many mosses are important to the early stages of soil formation
Hepatophyta LiverwortsSame as mosses
Anthocerotophyta HornwortsAlso a member of Bryophyta
Equisetophyta HorsetailsIdentifiable root, leaf and stem systems but still produce spores instead of seed
Pteridophyta FernsSame as horsetails
Coniferophyta ConifersIncludes Pinales, Taxales, Cupressaceae and hundreds of other species. Reproduce by producing seeds most often in cones, many have adaptations to tolerate water loss
Ginkgophyta GinkgoOnly member is the ginkgo biloba
Angiosperms Flowering plantsIncludes around 25,000 species divided into two main classes the monocotyledons and dicotyledons, produce seeds that are protected by fruits

Identification, classification and description of plants

Three goals of plant taxonomy are the identification, classification and description of plants. The distinction between these three goals is important and often overlooked.

1.Plant identification is a determination of the identity of an unknown plant by comparison with previously collected specimens or with the aid of books or identification manuals. The process of identification connects the specimen with a published name. Once a plant specimen has been identified, its name and properties are known.

2.Plant classification is the placing of known plants into groups or categories to show some relationship. Scientific classification follows a system of rules that standardizes the results, and groups successive categories into a hierarchy. For example, the family to which the lilies belong is classified as follows:

The classification of plants results in an organized system for the naming and cataloging of future specimens, and ideally reflects scientific ideas about inter-relationships between plants. The set of rules and recommendations for formal botanical nomenclature, including plants, is governed by the International Code of Nomenclature for algae, fungi, and plants abbreviated as ICN.

3.Plant description is a formal description of a newly discovered species, usually in the form of a scientific paper using ICN guidelines. The names of these plants are then registered on the International Plant Names Index along with all other validly published names.

Classification systems

These include;

Online databases

See Category: Online botany databases

See also

Related Research Articles

Dioscoreales Order of lilioid monocotyledonous flowering plants

The Dioscoreales are an order of monocotyledonous flowering plants in modern classification systems, such as the Angiosperm Phylogeny Group and the Angiosperm Phylogeny Web. Within the monocots Dioscoreales are grouped in the lilioid monocots where they are in a sister group relationship with the Pandanales. The Dioscoreales must contain the family Dioscoreaceae which includes the yam (Dioscorea) which is an important food source in many regions. Older systems tended to place all lilioid monocots with reticulate veined leaves in Dioscoreales. As currently circumscribed by phylogenetic analysis using combined morphology and molecular methods, Dioscreales contains many reticulate veined vines in Dioscoraceae, it also includes the myco-heterotrophic Burmanniaceae and the autotrophic Nartheciaceae. The order consists of three families, 22 genera and about 850 species.

Santalales Order of flowering plants

The Santalales are an order of flowering plants with a cosmopolitan distribution, but heavily concentrated in tropical and subtropical regions. It derives its name from its type genus Santalum (sandalwood). Mistletoe is the common name for a number of parasitic plants within the order.

Cornales Order of flowering plants

The Cornales are an order of flowering plants, early diverging among the asterids, containing about 600 species. Plants within the Cornales usually have four-parted flowers, drupaceous fruits, and inferior to half-inferior gynoecia topped with disc-shaped nectaries.


Under the International Code of Nomenclature for algae, fungi, and plants (ICN), Rosidae is a botanical name at the rank of subclass. Circumscription of the subclass will vary with the taxonomic system being used; the only requirement being that it includes the family Rosaceae.

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 flowering plants in the rosid subclade of eudicots

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.

Burmanniaceae Family of flowering plants

Burmanniaceae is a family of flowering plants, consisting of 99 species of herbaceous plants in eight genera.

Angiosperm Phylogeny Group Collaborative research group for the classification of flowering plants

The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships discovered through phylogenetic studies.

Asphodelaceae Family of flowering plants in the order Asparagales

Asphodelaceae is a family of flowering plants in the order Asparagales. Such a family has been recognized by most taxonomists, but the circumscription has varied widely. In its current circumscription in the APG IV system, it includes about 40 genera and 900 known species. The type genus is Asphodelus.

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.

Schisandraceae Family of flowering plants

Schisandraceae is a family of flowering plants with 3 known genera and a total of 92 known species. Such a family has been recognized by most taxonomists, at least for the past several decades. Before that, the plants concerned were assigned to family Magnoliaceae and Illiciaceae.

Juncaginaceae Family of aquatic plants

Juncaginaceae is a family of flowering plants, recognized by most taxonomists for the past few decades. It is also known as the arrowgrass family. It includes 3 genera with a total of 34 known species.

Peridiscaceae Family of flowering plants in the order Saxifragales

Peridiscaceae is a family of flowering plants in the order Saxifragales. Four genera comprise this family: Medusandra, Soyauxia, Peridiscus, and Whittonia., with a total of 12 known species. It has a disjunct distribution, with Peridiscus occurring in Venezuela and northern Brazil, Whittonia in Guyana, Medusandra in Cameroon, and Soyauxia in tropical West Africa. Whittonia is possibly extinct, being known from only one specimen collected below Kaieteur Falls in Guyana. In 2006, archeologists attempted to rediscover it, however, it proved unsuccessful.

<i>Myrothamnus</i> Genus of shrubs

Myrothamnus is a genus of flowering plants, consisting of two species of small xerophytic shrubs, in the southern parts of tropical Africa and in Madagascar. Myrothamnus is recognized as the only genus in the family Myrothamnaceae.

Sympetalae Historical subclass of flowering plants with fused petals

Sympetaly is a flower characteristic that historically was used to classify a grouping of plants termed Sympetalae, but this term has been abandoned in newer molecular based classifications, although the grouping has similarity to the modern term asterids.

Anarthriaceae Family of grasses

The Anarthriaceae are a family of three genera, Anarthria, Hopkinsia and Lyginia of flowering plants, now included in Restionaceae following APG IV (2016). The family is accepted in the Angiosperm Phylogeny Group's classification system, APG III system, but is not considered a separate family in many other taxonomic systems. The three genera are herbaceous but differ greatly in characteristics.

James L. Reveal 20th century American botanist known for contributions to taxonomy

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.

Caryophyllales Order of flowering plants

Caryophyllales is a diverse and heterogeneous order of flowering plants that includes the cacti, carnations, amaranths, ice plants, beets, and many carnivorous plants. Many members are succulent, having fleshy stems or leaves. The betalain pigments are unique in plants of this order and occur in all its families with the exception of Caryophyllaceae and Molluginaceae.

Mesangiospermae One of two clades of flowering plants

Mesangiospermae is a clade of flowering plants (angiosperms), informally called "mesangiosperms". They are one of two main groups of angiosperms. It is a name created under the rules of the PhyloCode system of phylogenetic nomenclature. There are about 350,000 species of mesangiosperms. The mesangiosperms contain about 99.95% of the flowering plants, assuming that there are about 175 species not in this group and about 350,000 that are. While such a clade with a similar circumscription exists in the APG III system, it was not given a name.


  1. Principles of Horticulture, 4th Ed. Elsevier. p. 28.