United States, Michigan, Gratiot, Fulton Twp., ca. 1.5 mi. N. of Perrington.
Swamp forest.
sheet - 1
"Abundant on surface of small pool, with Lemna minor (!)" [Active barcode. On same sheet as W. borealis, Lemna minor and Spirodela polyrrhiza with inactive barcodes 1289611, 1289612 and 1289613 respectively ]