1. R. arvensis, Aust., Phil. Acad. Sc. XXI. 232.
On damp earth which has been covered by spring floods, east side of Leamy'sLake near Hull, Que., Sept., 24th, 1889. (Macoun.)
2. R. lutescens, Schweins
On the borders of muddy pools east of Belleville, Hastings Co., Ont., Aug. 13th, 1868. (Macoun.)
3. R. Austinii, Steph. Ontario. (Underwood.)
4. R. fluitans, Linn.
Very abundant in Patterson's Creek, Ottawa, Ont.; in the creek in the beaver meadow, west of Hull, Que.; very abundant in the marshes along the Bay of Quinte at Belleville, Ont., and on the south side of Massasauga Point, August 1st, 1873; in an old canal between Point Edward and Sarnia, Ont., August 14th, 1901; common in a pool at Sicamous, B. C. (Macoun.) In stagnant water near the round-house, Montrose, Ont., July, 1897. (R. Cameron)
5. R. Sullivantii, Aust.
On the muddy borders of pools east of Belleville, Hastings Co., Ont., July 16th, 1871; on a mud flat near McAdie's mill, Kennebec, Addington Co., Ont., July 11th, 1870. (Macoun.)
6. R. sorocarpa, Bisch.
Scoresby Sound, East Greenland, Lat. 700 15'. (C. Jansen.)