This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
The Common Walnut (J. regia), from western Asia, is the best-known kind, and is referred to in more detail in Vol. Ill, p. 206, as a fruit tree. Other valuable ornamental Walnuts are nigra, 60-100 ft. high, North America; cinerea, very similar in appearance; cordiformis and Sie-boldiana, from Japan; and mandschurica, from Amur. Raised from seeds.