Coefficient of Conservatism:
Coefficient of Wetness:
B. S. Walters
Stream banks and swamps, as well as upland beech-maple, oak-hickory, and mixed hardwood stands. The Alpena and Benzie Co. records, and probably also the North Manitou Island plants, are of individuals seeding in from planted trees,. At least some, if not all, of the Upper Peninsula records, however, appear to be of native trees.
There are some pubescence differences that will help to distinguish this species from the black walnut, even when the distinctive dark pith is not exposed. In J. cinerea, there is often a pad of dense small hairs extending transversely along the upper margin of the old leaf scars; in J. nigra, this pad is absent, although the circular area of bud pubescence is confusing, and some specimens are ambiguous. The underside of the leaflets in J. cinerea is covered with mostly stellate hairs, while in J. nigra the pubescence is sparser and mostly of simple hairs. The pubescence of J. cinerea, including that on the fruit, is stickier than that of J. nigra. Butternuts in Michigan are being decimated by Butternut canker (Sirococcus clavigignenti-juglandacearum), a fungus that produces stem cankers that girdle and kill adult trees.