''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, e.g., including only woody plants with secondary growth, only ...

s now

native Native may refer to: People * '' Jus sanguinis'', nationality by blood * '' Jus soli'', nationality by location of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Nat ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

, 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 as ...

'', is

near threatened A near-threatened species is a species which has been Conservation status, categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to Endangered species, endangerment in the ne ...

in the wild, but is widely cultivated in China for its

bark Bark may refer to: Common meanings * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Arts and entertainment * ''Bark'' (Jefferson Airplane album), ...

, and is highly valued in

herbology Herbal medicine (also called herbalism, phytomedicine or phytotherapy) is the study of pharmacognosy and the use of medicinal plants, which are a basis of traditional medicine. Scientific evidence for the effectiveness of many herbal treatments ...

such as

traditional Chinese medicine Traditional Chinese medicine (TCM) is an alternative medicine, alternative medical practice drawn from traditional medicine in China. A large share of its claims are pseudoscientific, with the majority of treatments having no robust evidence ...

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 Leaf, 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 or ovate, a term for ancient Celtic bards ...

with an

acuminate The following terms are used to describe leaf plant morphology, morphology in the description and taxonomy (biology), taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade ...

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. Latices are found in nature, but synthetic latices are common as well. In nature, latex is found as a wikt:milky, milky fluid, which is present in 10% of all floweri ...

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. Types of polyisoprene ...

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

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s being inconspicuous, small, and greenish. The

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

s ripen between June and November and are a winged

samara Samara, formerly known as Kuybyshev (1935–1991), is the largest city and administrative centre of Samara Oblast in Russia. The city is located at the confluence of the Volga and the Samara (Volga), Samara rivers, with a population of over 1.14 ...

with one

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

, very similar to an

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

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 certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

, 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, which is primarily used to create a high-quality latex of the same name. The material is rigid, naturally biologically Chemically inert, inert, resilient, electrically n ...

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 p ...

. *''Eucommia'' **†'' Eucommia constans'' (Miocene-Pliocene; Mexico) **†'' Eucommia eocenica'' (Middle Eocene; Mississippi Embayment) **†'' Eucommia europaea'' (Oligocene; Europe) **†'' Eucommia jeffersonensis'' (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 ea ...

'' (Early-Late Eocene; western North America) **†'' Eucommia rolandii'' (Early-Middle Eocene; Mississippi and British Columbia) **''

'' (Living, central-eastern China)

Medicinal use

Eucommia tea has been shown to somewhat lower blood pressure. It has been used and sold for a various other things. Research appears to be somewhat limited.

Distribution

''Eucommia 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. is ...

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 bot ...

s in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, 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 preserve ...

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

brown coal Lignite (derived from Latin ''lignum'' meaning 'wood'), often referred to as brown coal, is a soft, brown, Combustion, combustible sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35% and is considered ...

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

{{Authority control Garryales Asterid genera Trees of China Near threatened plants Taxa named by Daniel Oliver