Eucommia

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Eudicots
Cladus: Core eudicots
Cladus: Asterids
Cladus: Lamiids
Ordo: Garryales

Familia: Eucommiaceae
Genus: Eucommia
Species: E. ulmoides
Paleospecies: †E. constans – †E. eocenica – †E. europaea – †E. jeffersonensis – †E. montana – †E. rolandii

Name

Eucommia Oliv. Hooker's Icon. Pl. 20: pl. 1950. (1890)

Type species: Eucommia ulmoides Oliv.

References
Primary references

Oliver, D., 1890. Hooker's Icon. Pl. 20: t. 1950.

Additional references

Call, V.B. & Dilcher, D.L. 1997. The fossil record of Eucommia (Eucommiaceae) in North America. American Journal of Botany 84(6): 798–814. DOI: 10.2307/2445816 PDF JSTOR Reference page.

Links

Govaerts, R. et al. 2020. Eucommia in World Checklist of Selected Plant Families. The Board of Trustees of the Royal Botanic Gardens, Kew. Published online. Accessed: 2020 Jun 03. Reference page.
Hassler, M. 2020. Eucommia. World Plants: Synonymic Checklists of the Vascular Plants of the World In: Roskovh, Y., Abucay, L., Orrell, T., Nicolson, D., Bailly, N., Kirk, P., Bourgoin, T., DeWalt, R.E., Decock, W., De Wever, A., Nieukerken, E. van, Zarucchi, J. & Penev, L., eds. 2020. Species 2000 & ITIS Catalogue of Life. Published online. Accessed: 2020 Jun 03. Reference page.

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 its bark, and is highly valued in herbology such as traditional Chinese medicine.[3]

Description

Modern Eucommia trees grow to about 15 m tall. The leaves are deciduous, arranged alternately, simple ovate with an acuminate tip, 8–16 cm (3.1–6.3 in) long, and with a serrated margin. If a leaf is torn across, strands of latex exude from the leaf veins and solidify into rubber and hold the two parts of the leaf together. It flowers from March to May with the flowers being inconspicuous, small, and greenish. The fruits ripen between June and November and are a winged samara with one seed, very similar to an elm samara in appearance. The modern fruits are 2–3 cm (0.79–1.18 in) long and 1–2 cm (0.39–0.79 in) broad, while fruits of the extinct species range up to 21 millimetres (0.83 in) long.[3]

Eucommia is dioecious, with separate male and female plants.[4]
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",[3] "Gutta-percha tree" or "Chinese rubber tree", but is not related to either the true Gutta-percha tree of southeastern Asia, nor to the South American rubber tree.

Eucommia
†Eucommia constans (Miocene-Pliocene; Mexico)
†Eucommia eocenica (Middle Eocene; Mississippi Embayment)
†Eucommia europaea (Oligocene; Europe)
†Eucommia jeffersonensis (latest Eocene; Oregon)
†Eucommia montana (Early-Late Eocene; western North America)
†Eucommia rolandii (Early-Middle Eocene; Mississippi and British Columbia)
Eucommia ulmoides (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.[3] E. ulmoides is also occasionally planted in botanical gardens and other gardens in Europe, North America, and elsewhere, being of interest as the only cold-tolerant (to at least -30 °C) rubber-producing tree. Fossil species of Eucommia have been found in 10- to 35-million-year-old brown coal deposits in central Europe,[3] in numerous fossil sites in Asia,[3] and five different fossil species have been described from North America, indicating the genus had a much wider range in the past.[3]
References

IPNI Plant name details Eucommia. Retrieved 9 September 2013.
Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III". Botanical Journal of the Linnean Society. 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x.
Call, V.B.; Dilcher, D.L. (1997). "The fossil record of Eucommia (Eucommiaceae) in North America" (PDF). American Journal of Botany. 84 (6): 798–814. doi:10.2307/2445816. JSTOR 2445816. PMID 21708632. Archived from the original (PDF) on 2008-10-07. Retrieved 2012-09-10.

"Eucommiaceae". Flora of China. 9 March 2021 – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.

World Conservation Monitoring Centre (1998). "Eucommia ulmoides". IUCN Red List of Threatened Species. 1998: e.T31280A9614313. doi:10.2305/IUCN.UK.1998.RLTS.T31280A9614313.en.
International Plant Names Index. 2020. Eucommia. Published online. Accessed: Jun 03 2020.
Tropicos.org 2020. Eucommia. Missouri Botanical Garden. Published online. Accessed: 03 Jun 2020.