29 September 1997.
Illinois, United States
Locality: Clarence at the junction of Illinois Highways 9 and 49, Section 17, Button Township, T23N, R11E, Rankin Quad, Ford County.
Coordinates: 40.4500, -87.9667
(Map it)
Elevation: 234m.
Environment description: Soybean field margin.
Number of plants sampled: 60
Comment: Pop 33. Mixed with Pop 32. Infestation of thousands.
Collector(s):