United States, Wisconsin, Jefferson, Township of Cold Spring; [T5N R16E Palmyra Twp. overwritten to Cold Spring Twp. T6N R17E which would be in Waukesha County, editor used T5N R15E Cold Springs Twp.]
Along the edge of an irrigation ditch at the water line.
Collection date 1971. [Mixed collection with C. Cyperus erythrorhizos (UWSP017507a) and C. odoratus "?" (UWSP017507)].