(2717.) Z. aquatica, Linn.; Pursh, Fl. I., 60.

Z. clavulosa, Michx., Fl. I., 75.

Hydropyrum esculentum, Link.; Hook., Fl. II., 233.

Very abundant in many marshes and lakes throughout Ontario. Abundant in water at Hampton, and other places in King's Co.; not rare at Salmon River, N.B. (Fowler, Cat.) Beauport, Q.; and Island of Orleans. (St. Cyr.) St. Andrews, Q. (McGill Coll. Herb.) Borders of rivers and brooks, near Ottawa. (Fletcher, Fl. Ott.) Very abundant in the Bay of Quinte, and Bice Lake, and throughout the whole length of the Trent and all its tributaries; common in marshes all around the Great Lakes, and nine miles west of Fort William, Thunder Bay. (Macoun.) Marsh at the mouth of the Mississaugi River, Georgian Bay. (R. Bell.) Marshes, Burlington Bay, Hamilton, Ont. (Logie.) Marshes at Kingston, and Picton, Ont. (Mlllman.) Toronto marsh, and Point aux Pins, Lake Erie. (Burgess.) Lake of the Woods, Rosseau River, Man. (Burgess. Dawson.) Lake Huron. (Hooker, Fl.) Newfoundland. (Reeks.)