EUCOMMIA ULMOIDES (HARDY RUBBER-TREE; EUCOMMIACEAE) AS AN ESCAPE IN NORTH AMERICA

摘要

Eucommia ulmoides Oliver (Fig. 1) is the sole living member of the genus Eucommia Oliver and the family Eucommiaceae. This genus is thought to have been native to mountain forests in central and western China, in open forests and in valleys, at elevations of 200-2500 m (Ying et al. 1993). It was first brought to the attention of western botanists by Augustine Henry in 1886 (Forrest 1995), shortly after which it was described by Oliver (1890), and was introduced into cultivation in Europe in 1892 and the United States in 1896 (Forrest 1995; Poor 1997; Rehder 1947). The species was thought to be extinct in the wild, surviving only through cultivation (Mabberley 1997; Poor 1997; Sargent 1913), but native stands may still exist (Swink et al. 1978; Varossieau 1942). Fossil remains of the genus have been found in North America, Europe, and Asia, evidence that the genus was widespread in the Cenozoic and that its present-day distribution is re-lictual (Call & Dilcher 1997). It is called hardy rubber-tree in many sources, though Barker (1984) suggested that it be called "hardy gutta tree," "gutta-percha tree," or "Chinese threadtree."