(2411.) A. Calamus, Linn.; Hook., Fl. II., 167; Pursh, Fl. I., 235.

Abundant in marshes by rivers and lakes. Pennant Harbor, Halifax Co., N.S. (Sommers.) Abundant in a marsh at Truro and near Yarmouth, N.S. (Macoun.) Common on the borders of lakes and ponds, Kouchibouguac, Kennebeccasis, and Hopewell, N.B. (Fowler, Cat.) Shallow lake, Fraserville, Q. (Thomas.) Sandy banks of the River Rouge, Argenteuil Co., Q. (D'Urban.) Abundant in marshes around Ottawa. (Fletcher, Fl. Ott.) Margin of St. Lawrence River, and small streams near Prescott, Ont. (Billings.) Common in marshes of the Bay of Quinte, and on the shores of Lake Ontario and all still waters inland, north of the lake. (Macoun.) Vicinity of Hamilton, (Buchan.) Chatham, Ont. (McGill Coll. Herb.) Swamps at Kingston, Ont. (Burgess, Millman.) Point Pelee marshes, Lake Erie. (Burgess.) Sydenham River, Owen Sound, Ont. (Macoun.) Oba River, Ont. (B. Bell.) Lake of the Woods. (Dawson, Burgess.) Canada to the Saskatchewan. (Hooker, Fl.)