(2452.) Z. palustris, Linn.; Pursh, Fl. I., 4; Hook., Fl. II., 170.

Freshwater, and brackish ponds and ditches; not rare. In the salt marsh near Truro, and at Yarmouth, N.S.; salt ponds at Baddeck, Cape Breton. (Macoun & Burgess.) Growing under water in streams rendered brackish by the tides. Eichibucto and Spurr's Cove, N.B. (Fowler, Cat.) Salt Lake, Anticosti. (Macoun.) Not uncommon at Ottawa. (Fletcher, Fl. Ott.) Pools by the St. Lawrence River, at Pres-cott, Ont. (Billings.) Marshy ponds near Rednersville, Bay of Quinte, and in a ditch between Taylor's Hill and the River Moira, Belleville, Ont. (Macoun.) Lake Mistassini, N.E.T.; Moose Mountain Creek, Man. (J. M. Macoun.) In "The River that Turns," near the Elbow of the South Saskatchewan, and numerous brackish ponds throughout the prairie region. (Macoun.)