Eucommia

Eucommia (Eucommia ulmoides) is a small tree native to China. It is extinct in the wild, but is widely cultivated in China for its bark, highly valued in herbology such as Traditional Chinese medicine (TCM).

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Eucommia is the sole member of the family Eucommiaceae, and was formerly considered to be a separate order, the Eucommiales. It is one of the 50 fundamental herbs used in Chinese herbology, where it is called dùzhòng (杜仲).

Eucommia grows to about 15 m tall. The leaves are deciduous, arranged alternately, simple ovate with an acuminate tip, 8–16 cm long, and with a serrated margin. If a leaf is torn across, strands of latex exuded from the leaf veins solidify into rubber and hold the two parts of the leaf together. The flowers are inconspicuous, small and greenish; the fruit is a winged samara with one seed, very similar to an elm samara in appearance, 2–3 cm long and 1–2 cm broad.

Eucommia 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.

It is also sometimes known as "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.

Fossils of Eucommia have been found in 10–35 million year old brown coal deposits in central Europe and widely in North America (Call & Dilcher 1997), indicating that the genus had a much wider range in the past.

Ethnomedical Use

The bark is used in traditional Chinese medicine to treat lower back pain, aching knees, and to prevent miscarriage. Also used to "tonify" the Yang.

References and external links

• World Conservation Monitoring Centre (1998). Eucommia ulmoides. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006.
• Call, V.B. and Dilcher, D.L. 1997. The fossil record of Eucommia (Eucommiaceae) in North America. American Journal of Botany 84(6): 798-814. Available online (pdf file)