The cut-leaved nightshade, Solanum triflorum Nutt., was found in September 1941, in Rock Township, Cherokee County, Iowa. This nightshade was discovered growing in a pasture where there was a mixture of Clarion and Marshall soil types on the top of a bluff about twenty feet high where the soil was thin and gravelly.
Proceedings of the Iowa Academy of Science
Stiles, Nester L. and Bakke, Arthur L.
"The Cut-Leaved Nightshade (Solanum triflorum Nutt.),"
Proceedings of the Iowa Academy of Science, 49(1), 213-214.
Available at: https://scholarworks.uni.edu/pias/vol49/iss1/29