''Eucommia'' is a genus of small

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

s now

native Native may refer to: People * Jus soli, citizenship by right of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Native Americans (disambiguation) In arts and entert ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

, with a fossil record that shows a much wider distribution. The single living species, ''

Eucommia ulmoides ''Eucommia ulmoides'' is a species of small tree native to China. It belongs to the monotypic family Eucommiaceae. It is considered vulnerable in the wild, but is widely cultivated in China for its bark and is highly valued in herbology such ...

'', is

near threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify fo ...

in the wild, but is widely cultivated in China for its bark, and is highly valued in

herbology Herbal medicine (also herbalism) is the study of pharmacognosy and the use of medicinal plants, which are a basis of traditional medicine. With worldwide research into pharmacology, some herbal medicines have been translated into modern remed ...

such as

traditional Chinese medicine Traditional Chinese medicine (TCM) is an alternative medical practice drawn from traditional medicine in China. It has been described as "fraught with pseudoscience", with the majority of its treatments having no logical mechanism of action ...

Description

Modern ''Eucommia'' trees grow to about 15 m tall. The leaves 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 leaves, usually in the autumn; to the shedding of petals, aft ...

, arranged alternately, simple

ovate Ovate may refer to: *Ovate (egg-shaped) leaves, tepals, or other botanical parts *Ovate, a type of prehistoric stone hand axe *Ovates, one of three ranks of membership in the Welsh Gorsedd *Vates In modern English, the nouns vates () and ovat ...

with an

acuminate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...

tip, long, and with a serrated margin. If a leaf is torn across, strands of

latex Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well. In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...

exude from the leaf veins and solidify into

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

and hold the two parts of the leaf together. It flowers from March to May with the

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s being inconspicuous, small, and greenish. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

s ripen between June and November and are a winged

samara Samara ( rus, Сама́ра, p=sɐˈmarə), known from 1935 to 1991 as Kuybyshev (; ), is the largest city and administrative centre of Samara Oblast. The city is located at the confluence of the Volga and the Samara (Volga), Samara rivers, with ...

with one

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

, very similar to an

elm Elms are deciduous and semi-deciduous trees comprising the flowering plant genus ''Ulmus'' in the plant family Ulmaceae. They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical-montane regions of North ...

samara in appearance. The modern fruits are long and broad, while fruits of the extinct species range up to long. ''Eucommia'' is

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

, with separate male and female plants.

Taxonomy

''Eucommia'' is the sole member of the family Eucommiaceae, and was formerly considered to be a separate order, the Eucommiales. The modern species is sometimes known as the "hard rubber tree", "Gutta-percha tree" or "Chinese rubber tree", but is not related to either the true

Gutta-percha Gutta-percha is a tree of the genus ''Palaquium'' in the family Sapotaceae. The name also refers to the rigid, naturally biologically inert, resilient, electrically nonconductive, thermoplastic latex derived from the tree, particularly from ' ...

tree of southeastern Asia, nor to the South American

rubber tree ''Hevea brasiliensis'', the Pará rubber tree, ''sharinga'' tree, seringueira, or most commonly, rubber tree or rubber plant, is a flowering plant belonging to the spurge family Euphorbiaceae originally native to the Amazon basin, but is now pa ...

. *''Eucommia'' **†''

Eucommia constans ''Eucommia constans'' is an extinct species of flowering plant in the family Eucommiaceae. ''Eucommia'' is a genus of small trees now native to China, with a fossil record that shows a much wider distribution. ''E. constans'' is known from fo ...

'' (Miocene-Pliocene; Mexico) **†''

Eucommia eocenica ''Eucommia eocenica'' is an extinct species of flowering plant in the family Eucommiaceae. ''E. eocenica'' is known from fossil fruits found in the middle Eocene Claiborne Formation deposits of the southeastern United States. ''E. eocenica'' ...

'' (Middle Eocene; Mississippi Embayment) **†''

Eucommia europaea ''Eucommia'' is a genus of small trees now native to China, with a fossil record that shows a much wider distribution. The single living species, ''Eucommia ulmoides'', is near threatened in the wild, but is widely cultivated in China for it ...

'' (Oligocene; Europe) **†''

Eucommia jeffersonensis ''Eucommia jeffersonensis'' is an extinct species of flowering plant in the family Eucommiaceae. It is known from a fossil fruit found in latest Eocene deposits of Oregon, United States. ''E. jeffersonensis'' is one of five described fo ...

'' (latest Eocene; Oregon) **†''

Eucommia montana ''Eucommia montana'' is an extinct species of flowering plant in the family Eucommiaceae. ''E. montana'' is known from fossil fruits found in Eocene deposits of the northwestern United States southeastern British Columbia south to Oregon and e ...

'' (Early-Late Eocene; western North America) **†''

Eucommia rolandii ''Eucommia rolandii'' is an extinct species of flowering plant in the family Eucommiaceae. ''E. rolandii'' is known from four fossil leaves found in Middle Eocene deposits of British Columbia, Canada and Mississippi, United States. ''E. rolan ...

'' (Early-Middle Eocene; Mississippi and British Columbia) **''

'' (Living, central-eastern China)

Distribution

''E. ulmoides'' is native to forest areas on hills and mountains of the provinces in central and eastern China, though it has been suggested that the species is extinct in the wild. ''E. ulmoides'' is also occasionally planted in

botanical garden A botanical garden or botanic gardenThe terms ''botanic'' and ''botanical'' and ''garden'' or ''gardens'' are used more-or-less interchangeably, although the word ''botanic'' is generally reserved for the earlier, more traditional gardens, an ...

s and other

garden A garden is a planned space, usually outdoors, set aside for the cultivation, display, and enjoyment of plants and other forms of nature. The single feature identifying even the wildest wild garden is ''control''. The garden can incorporate both ...

s in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, and elsewhere, being of interest as the only cold-tolerant (to at least -30 °C) rubber-producing tree.

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

species of ''Eucommia'' have been found in 10- to 35-million-year-old

brown coal Lignite, often referred to as brown coal, is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35%, and is considered the lowest rank of coal due to its relatively low heat ...

deposits in central

, in numerous fossil sites in Asia, and five different fossil species have been described from

, indicating the genus had a much wider range in the past.

References

External links

{{Taxonbar, from=Q5406185 Garryales Asterid genera Trees of China Near threatened plants Taxa named by Daniel Oliver