L. . Butternut and black walnut (Juglans nigra) are very similiar,
but can be distinguished by certain morphological differences.
Butternut has a pad of small dense hairs extending crosswise along the
upper margin of the old leaf scars; in black walnut this pad is absent.
The underside leaflets of butternut are densely covered with stellate
hairs, while in black walnut leaflet hairs are almost inconspicuous
Recognized hybrids are as follows :
J. cinerea x J. regia = J. X quadrangulata
J. cinerea x J. ailantifolia = J. X bixbi
Reports of crosses between butternut and black walnut have not been
- 16. Little, Elbert L., Jr. 1979. Checklist of United States trees (native and naturalized). Agric. Handb. 541. Washington, DC: U.S. Department of Agriculture, Forest Service. 375 p. 
- 24. Rink, George. 1990. Juglans cinera L. Butternut. In: Burns, Russell M.; Honkala, Barbara H., technical coordinators. Silvics of North America. Vol. 2. Hardwoods. Agric. Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest Service: 386-390. 
- 31. Voss, Edward G. 1985. Michigan flora. Part II. Dicots (Saururaceae--Cornaceae). Bull. 59. Bloomfield Hills, MI: Cranbrook Institute of Science; Ann Arbor, MI: University of Michigan Herbarium. 724 p. 
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