In 1901 there was begun a study of the germination of weed seeds under different conditions. It was observed that a large number of the weed seeds did not germinate freely in the fall.
Proceedings of the Iowa Academy of Science
©1910 Iowa Academy of Science, Inc.
Pammel, L. H. and King, Charlotte M.
Proceedings of the Iowa Academy of Science, 17(1), 20-33.
Available at: https://scholarworks.uni.edu/pias/vol17/iss1/8