Canada, Ontario, Leeds and Grenville, ca. 4 miles SW of Bishop Mills (= ca. 40 miles S of Ottawa).
Abundant in shallow marshy water of Middle Kemptville Creek, where it has obviously been present for several years.
sheet - 1
female only "Many flowers in early bloom, mainly staminate; a few pistillate flowers on separate stems (dioecious) & recognizable at a distance by the attitude of their petals & swelling ovary beneath."