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EUCOMMIAOEAE. 



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EUCOMMIA. 



(Family Eucommiaceae). 



Tree: deciduous. Twigs moder- 

 ate, terete, somewhat zig-zag: pith 

 pale, rounded, chambered. Buds 

 solitary, sessile, ovoid, moderate, 

 with some half-dozen exposed 

 scales, the end-bud absent. Leaf- 

 scars alternate, often 2-ranked, 

 rather small, half-elliptical, little 

 raised: bundle-trace 1, C-shaped: 

 stipule-scars lacking. 



Eucommia has attracted atten- 

 tion because of the occurrence in 

 its organs of a peculiar type of 

 rubber-producing cells, which ap- 

 pear as delicate elastic cords 

 when leaf or twig is broken. Ac- 

 cording to Weiss, who published 

 an account of them in 1892 in the 

 botanical series of the Transac- 

 tions of the Linnean Society, 

 these cells differ morphologically 

 from the latex tissue of other plants in that they originate 

 here from new initials in the developing organs, while in 

 other cases their development is progressive and continuous 

 from a few initial cells formed in the embryo. 



The name ulmoides is given because of the elm-like habit 

 of growth of the tree, which is of recent introduction but is 

 proving hardy and so is likely to find an extended use. 

 Though no industrial application may be made of it, the fact 

 that Eucommia contains rubber is not to be overlooked at a 

 time when every possible source of that essential substance is 

 being investigated. 

 Glabrous: twigs red-brown, with pale lenticels. E. ulmoides. 



