Juglans regia Juglans regia Juglans regia, the Persian walnut, English walnut, Circassian walnut, or especially in Great Britain, common walnut, is an Old World walnut tree species native to the region stretching from the Balkans eastward to the Himalayas and southwest China. The largest forests are in Kyrgyzstan, where trees occur in extensive, nearly pure, walnut forests at 1,000–2,000 m (3000 to 7000 ft) altitude—notably at Arslanbob in Jalal-Abad Province. It is widely cultivated across Europe. "Juglans regia" is a large, deciduous tree attaining heights of 25–35 m (80 to 120 ft), and a trunk up to 2 m (6 ft) diameter,
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