Theaceae (), the tea family, is a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s comprising shrubs and trees, including the economically important tea plant, and the ornamental camellias. It can be described as having from seven to 40

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

, depending on the source and the method of circumscription used. The family Ternstroemiaceae has been included within Theaceae;Royal Botanic Gardens, Kew. ''Vascular Plant Families and Genera''
Theaceae
Watson, L., & Dallwitz, M. J. (1992 onwards). ''The families of flowering plants''

/ref> however, the

APG III system The APG III system of flowering plant classification is the third version of a modern, mostly molecular-based, system of plant taxonomy being developed by the Angiosperm Phylogeny Group (APG). Published in 2009, it was superseded in 2016 by a f ...

of 2009 places it instead in Pentaphylacaceae. Most but not all species are native to China and East Asia.

Family traits

Plants in this family are characterized by simple leaves that are alternate spiral to distichous, serrated, and usually glossy. Most of the genera have

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

foliage, but '' Stewartia'' and '' Franklinia'' are

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

. The toothed margins are generally associated with a characteristic Theoid leaf tooth, which is crowned by a glandular, deciduous tip. The flowers in this family are usually pink or white and large and showy, often with a strong scent. The calyx consists of five or more sepals, which are often persistent in the fruiting stage, and the corolla is five-merous, rarely numerous. Plants in Theaceae are multistaminate, usually with 20-100+ stamens either free or adnate to the base of the corolla, and are also distinctive because of the presence of pseudopollen. The pseudopollen is produced from connective cells, and has either rib-like or circular thickenings. The ovary is often hairy and narrows gradually into the style, which may be branched or cleft. The carpels are typically opposite from the petals, or the sepals in the case of ''

Camellia ''Camellia'' (pronounced or ) is a genus of flowering plants in the family Theaceae. They are found in tropical and subtropical areas in East Asia, eastern and South Asia, southern Asia, from the Himalayas east to Japan and Indonesia. There are ...

''. The fruits are loculicidal capsules, indehiscent baccate fruits or sometimes

pome In botany, a pome is a type of fruit produced by flowering plants in the subtribe Malinae of the family Rosaceae. Pome fruits consist of a central "core" containing multiple small seeds, which is enveloped by a tough membrane and surrounded by a ...

-like. The seeds are few and sometimes winged, or in some genera covered by fleshy tissue or unwinged and nude.

Genera

Eight genera are currently accepted:''Theaceae'' Mirb.
''

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

''. Retrieved 20 June 2023. *'' Apterosperma'' *''

'' , including ''Dankia'' , ''Piquetia'' (Pierre) H.Hallier, ''Thea'' L., ''Yunnanea'' Hu *'' Franklinia'' *'' Gordonia'' , including ''Laplacea'' * '' Polyspora'' *'' Pyrenaria'' , including ''Dubardella'' H.J.Lam, ''Glyptocarpa'' Hu, ''Parapyrenaria'' H.T.Chang, ''Sinopyrenaria'' Hu, ''Tutcheria'' Dunn *'' Schima'' *'' Stewartia'' , including ''Hartia'' Dunn The fossil '' Pentapetalum trifasciculandricus'', about 91 million years old, may belong to the Theaceae or the Pentaphylacaceae.

Distribution

Members of the family are found in Southeast Asia and Malesia, tropical South America and the Southeast United States. Three genera ('' Franklinia'', '' Gordonia'' and '' Stewartia'') have species native to the Southeast United States, with ''Franklinia'' being

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

there, and under some interpretations, also ''Gordonia'' with the Asian species formerly included in that genus being transferred to ''Polyspora''.''Flora of China'
"Theaceae (draft)"
/ref>

Biochemistry

There is distinctive chemistry within the family Theaceae. Sometimes, single crystals of calcium oxalate are present in Theaceous plants.

Ellagic acid Ellagic acid is a polyphenol found in numerous fruits and vegetables. It is the dilactone of hexahydroxydiphenic acid. Name The name comes from the French term ''acide ellagique'', from the word ''galle'' spelled backward because it can be o ...

and common polyphenols including flavonols, flavones and proanthocyanins are widely distributed throughout the family.

Gallic acid Gallic acid (also known as 3,4,5-trihydroxybenzoic acid) is a trihydroxybenzoic acid with the formula C6 H2( OH)3CO2H. It is classified as a phenolic acid. It is found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plant ...

and

catechin Catechin is a flavan-3-ol, a type of secondary metabolite providing antioxidant roles in plants. It belongs to the subgroup of polyphenols called flavonoids. The name of the catechin chemical family derives from ''catechu'', which is the tannic ...

s only occur in ''Camellia'' sect. ''Thea (C. sinensis, C. taliensis'' and ''C. irrawadiensis''.) Caffeine and its precursors theobromine and theophylline are only found in sect. ''Thea'' and are not found in other species of ''Camellia'' or other Theaceae. Caffeine content in the tea bush makes up 2.5-4% of the leaf's dry weight, and this high content of catechins and caffeine in the tea bush is the result of

artificial selection Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant ...

by humans for these characters. Triterpenes and their glycosides (saponins) are found widely throughout the family in the seeds, leaves, wood and bark. Plants in this family are also known to accumulate aluminum and fluoride.

Economic importance

The best known

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

is ''

'', which includes the plant whose leaves are used to produce tea (''Camellia sinensis''). In parts of Asia, other species are used as a beverage, including ''C. taliensis, C. grandibractiata, C. kwangsiensis, C. gymnogyna, C. crassicolumna, C. tachangensis, C. ptilophylla'', and ''C. irrawadiensis''. Several

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

are grown widely as ornamentals for their flowers and handsome foliage.

References

{{Authority control Ericales families