(2428.) P. natans, Linn.; Michx., Fl. I., 101; Pursh, Fl. I., 120; Hook., Fl. II., 171.

Quite common in lakes, ponds, and stagnant pools, throughout the country. Cow Bay, and Halifax, N.S. (Sommers, Cat.) Marshes near Cape Blomidon, N.S., and in lakelets, North Sydney, Cape Breton;; in a pond at Salt Lake, Anticosti, and in lakelets along the Gaspé coast. Q. (Macoun.) In slow flowing waters, Salmon River, Kent Co., and! Clifton, KB. (Fowler, Cat.) River St. Pierre, near Montreal, 1821. (Dr. Holmes.) Abundant in the River Rouge, in quiet places, Arffenteuil Co., Q. (D'Urban.) Abundant around Ottawa. (Fletcher, Fl. Ott.) Railroad Bay, near Prescott, Ont. (Billings.) Very common in nearly all still waters throughout central Ontario. (Macoun.) Burlington Bay, near the beach, Hamilton, Ont. (Logie.) In still water at Kingston, Ont. (Millman.) Marshes at Point Edward, Lake Huron-(J. M. Macoun.) Still waters, Owen Sound, Ont., and in the Kaminis-tiqua River, fifteen miles from its mouth, and in Lake Hannah, Nipigon River. (Macoun.) Lake Missinaibi, Ont. (R. Bell.) Lake of the Woods. (Dawson.) Not uncommon in ponds throughout the prairie region and northward to Lake Athabasca; not uncommon in Lost Lake, Shawnigan Lake, Home Lake and Sproat Lake, Vancouver Island. (Macoun.) Near Victoria, Vancouver Island. (Fletcher.) Sitka. (Rothr. Alask.) Stagnant waters, Canada to Hudson Bay. (Hooker, Fl.)

Var. prolixus, Koch.; Gray, Man. Ed. V. 485. P. natans, var ß. (?) Hook., Fl. II., 171.

Collected in flowing water near Ottawa. (McGill Coll. Herb.) A form approaching this variety was sent from London, Ont., by Burgess (Macoun.) North West America. (Hooker, Fl.) Specimens should be gathered of all forms.

(2429.) P. Oakesianus, Robbins, Gray, Man. Ed. V., 485.

Apparently a rare species in Canada. In marshes at Ellis Bay, Anticosti, 1883. (Macoun.)

(2430.) P. Claytonii, Tuckerman, Amer. Journ. Sci. XLV., 38.

Not uncommon but seldom collected. Hampton, Salmon River, and Norton, N.B.; rather common. (Fowler, Gat.) In flowing water at Hull, Q.; abundant in streams, North Hastings; common in Gull River, between Gull Lake and Minden, Victoria Co.; in Gull Lake, Barrie, Addington Co.; also in the river connecting Lake Isaac and Sky Lake, Bruce Co., Ont. (Macoun.) Vicinity of Ottawa. (Fletcher, Fl. Ott.) Blackstone Lake, Muskoka, Ont. (Burgess.)

(2431.) P. Vaseyi,Robbins, Gray,Man. Ed. V., 485.

Apparently rare in Canada. Crow River, above the dam at the Iron Works, Marmora, July 19th, 1864; Big Mud Turtle Lake, Gull River, Victoria Co., Ont. (Macoun.) Rideau Canal, Ottawa. Form with floating leaves and fruit. (Fletcher, Fl. Ott.) In 1865 this species was sent to Sir William Hooker as P. diversifolius, Barton, and believed by him to be that species, but later investigation showed that Barton's species went with P. hybridus. About the same time specimens were sent to Mr. W. M. Canby and Dr. Vasey, under the name mentioned above, and are likely in their collections now.

(2432.) P. Spirillus, Tuckerman, Amer. Journ. Sci.VI. (2,Ser.) 228.

P. diversifolius, Hook., Fl. II., 172.

A lovely species growing in flowing water, chiefly in the Laurentian districts of Ontario. In the Kennebeccasis at Norton; Lake Utopia and Salmon River, N.B. (Fowler, Cat.) Abundant in the Grand River, at Ottawa. (Fletcher, Fl. Ott.) In flowing water at Hull, Q.; in numerous streams, North Hastings, at Partridge Lake, Grimpsthorpe and in Crow River at Marmora Iron Works; Gull River, at Elliott's Falls, and in Mountain Lake above Minden, Victoria Co., Ont. (Macoun.) Norway House, head of Lake Winnipeg, to Canada. (Hooker, Fl.)

(2433.) P. hybridus, Michx., Fl. I., 101.

P. setaceus, Pursh, Fl. I., 120.

P.filiformis, Pursh, Herb.; Tucker. Amer. Journ. Sci. VI. (2, Ser.) 230.

St. James, and St. Stephens, N.B. ( Vroom.) Although we strongly suspect that the plants referred here are P. Spirillus, there is no reason to doubt the occurrence of the species so far north.

(2434.) P. rufescens, Schrader; Hook., Fl. II, 172.

P.fluitans, Pursh, Fl. I., 120.

P. natans, var. fluitans, Torrey.; Bot. N. York II., 254.

Apparently a rare but widely diffused species. St. Stephen, N.B. ( Vroom.) In flowing waters, Truro, N.S.; River Ste. Anne des Monts, Gaspé, Q.; abundant in flowing water in the River Trent, at the "Narrows" and in Crow River at Marmora Iron Works; also in the North River, Belmont and in Big Bushkong Lake, Victoria Co., Ont.; Current River, Lake Superior. (Macoun.) River Mistassini, near Lake St. John, Q. (Michaux.) Rapids of the Niagara River, near Bath Island. (Tuckerman.) Lake Mistassini, N.E.T. (J. M. Macoun.) Michi-picotin River, Ont., and Nelson River, Keewatin. (R. Bell.) Abundant in the mill stream at Nanaimo, Vancouver Island. (Macoun.) Ounalashka. (Rothr. Alask.) Stagnant waters, Canada to Hudson Bay. (Hooker, Fl.)

(2435.) P. lonchites, Tuckerman, Amer. Journ. Sci. VI. (2, Ser.) 226.

Apparently very rare or overlooked. Tobique Lakes, N.B. (Hay.) Abundant at Ottawa."A form with remarkably long stipules. (Fletcher, Fl. Ott.) In ponds, London. Ont. (Burgess.) Niagara Rapids, near Bath Island, Niagara River. (Tuckerman.)

(2436.) P. amplifolius, Tuckerman, Amer. Journ. Sci. VI. (2, Ser.) 226.

Not rare in deep and still water, but seldom collected. In the mill pond at Stirling; and Elziver, Hastings Co.; Gull Lake, Barrie, Adding-ton Co.; at the lower end of Big Bushkong Lake, Victoria Co., and in the Potawatamie River, above Jones Falls, Owen Sound, Ont. (Macoun.) In water, Parry Sound, Georgian Bay. (Burgess.) King's Mere and Meech's Lake, in the Chelsea Mountains, near Ottawa. (Fletcher, Fl Ott.) Missinaibi River and Lake, Ont. (R. Bell.) Marshes, Burlington Bay, Hamilton, Ont. (Logie.) Niagara River, on the Canadian side. (Tuckerman.) Near Victoria, Vancouver Island. (Fletcher.)

(2437.) P. gramineus, Linn.; Gray, M:in. Ed. V., 487.