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''Ulmus'' 'Columella' is a Dutch elm cultivar raised by the Dorschkamp Research Institute in Wageningen from a selfed or openly-pollinated seedling of the hybrid clone 'Plantyn' sown in 1967. It was released for sale in 1989 after proving extremely resistant to Dutch elm disease following inoculation with unnaturally high doses of the pathogen, ''Ophiostoma novo-ulmi''.〔Heybroek, H. (1993). The Dutch Elm Breeding Program. In Sticklen & Sherald (Eds.) (1993). ''Dutch Elm Disease Research'', Chapter 3. Springer Verlag, New York, USA.〕 ==Description== 'Columella' makes a tall, fastigiate tree with very upright branches, but broadens in later years () (). The rough, rounded, and curiously twisted leaves, < 7 cm long, are the result of a recessive gene inherited from its Exeter Elm ancestor, and are arranged in asymmetric clusters on short branchlets. The samarae, broadly obovate, are 13–17 mm long by 10–12 mm wide. Image:Columella leaves 1.jpg Image:Columella flowers.jpg Image:Columella samarae.jpg 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ulmus 'Columella'」の詳細全文を読む スポンサード リンク
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