Water willow is aquatic, in shallow still or slow moving spots. It is the most northern species of a genus of widespread tropicals. This is one of my long term disappointments. It's a Michigan threatened species that I have not found here in Lenawee. It occurs just to the east, downstream in the Raisin River, and just to the south in the Maumee system. But so far I've struck out here. Water willow grows in AL, AR, DE, FL, GA, IA(E), IL, IN, KS, KY, LA, MD, MI(T), MO, MS, NC, NJ, NY, OH, OK, PA, SC, TN, TX, VA, VT, WI, WV, ON(T), and QC(T). Mary Jane Thurston State Park, Lucas Co OH, 7/29/11.