Juglans ailantifolia caused by the fungus "Sirococcus clavigignenti-juglandacearum". This has led to its being planted as a replacement for butternuts in North America. The two species hybridise readily; the resulting hybrid "Juglans x bixbyi" (otherwise known as "J. cinerea x ailantifolia" or 'buartnut') is also resistant to canker and is likewise planted as a replacement for butternuts. Japanese walnut is distinguished from butternut by its larger leaves and round (not oval) nuts. Prospect Rock Permaculture in Vermont has been backcrossing buartnuts with native butternuts, resulting in 'butterbuarts', which will most likely bear greater resemblance to the butternut parentage, although may also be
Juglans olanchana Juglans olanchana Juglans olanchana is a semideciduous tree species in the Juglandaceae family. It can be found in Costa Rica, Guatemala, El Salvador, Honduras, Mexico and Nicaragua. It can grow up to 40 m in height and 1.5 m in diameter. The long branches bear twigs tipped with 40–50 cm long, glabrous, pinately compound leaves, darker on the top than on the bottom. The base of the trunk sometimes has buttresses. "Juglans olanchana" grows in wet and very wet tropical forests, most frequently on river banks, observed from 0–1400 m above sea level. Reports that it also grows in the