1916] St. John, — Potamogeton, Section Coleophylli 123 



1. P. Robbinsii Oakes, Hovey's Magaz. vii. 180 (1841). — Stem 

 stout, often freely branching : leaves linear, auricled at base, borne in 

 two ranks and stiffly divergent, 2-8 cm. long, 3-7 mm. wide, those of 

 the inflorescence reduced almost to narrow bracts; the margins 

 cartilaginous, finely and sharply serrate; midrib broad, flanked by 

 many fine secondary nerves; stipules white, many -nerved, soon 

 becoming deeply lacerate: flowering shoots with elongate internodes 

 and much reduced leaves, branching to produce several peduncles 

 1.5-5 cm. long: spikes short, 7-18 mm. long, loosely flowered, rarely 

 maturing fruit : fruit obliquely obovate, with a sharp central keel and 

 rounded lateral keels, 4 mm. long, 3 mm. wide; sides with a shallow 

 depression; beak subapical, 1 mm. long. — Generally distributed in 

 quiet waters from New Brunswick south to Delaware and west to 

 British Columbia and Oregon. 



Maine: pools in the Mattawamkeag River, below Island Falls, 

 Aroostook County, Sept. 25, 1901, M. L. Fernald (N); quiet pools in 

 Piscataquis River, Dover, Aug. 27, 1894, M. L. Fernald (N); in a 

 muddy pond, Plymouth, 1860, J. W. Chickering (H); East Wilton,. 

 Valley of the Sandy River, 1894, Kate Furbish (N); Haley Pond, 

 Rangely, 1894, Kate Furbish (N) ; Loon Lake, Rangely Lake Region, 

 Aug., 1894, Kate Furbish (N); the most abundant plant in the inlet 

 of Lambert Lake, Valley of the St. Croix River, Washington County, 

 Sept. 1, 1908, M. L. Fernald (N); in 5-7 feet of water, Biscay Pond, 

 Bristol, Sept. 6, 1898, E. B. Chamberlain, no. 822 (N); Torsey Pond, 

 Readfield, Sept., 1892, Kate Furbish (N); Messalonskee River, Water- 

 ville, Sept. 2, 1898, M. L. Fernald, no. 2,725 (N) ; South Poland, Valley 

 of the Androscoggin River, 1893, Kate Furbish (N); Androscoggin 

 Lake, North Leeds, Sept., 1894, Kate Furbish (N); West Baldwin, 

 Valley of the Saco River, Sept., 1900, Kate Furbish (N). New Hamp- 

 shire: Forest Lake, Dalton, Aug. 31, 1908, A. S. Pease, no. 11,580 

 (N); Pondicherry Pond, Jefferson, July, 1849, J. W. Robbing (A). 

 Vermont: Lake Champlain, Ferrisburg, Aug. 12, 1880, E. & C. E. 

 Faxon (H & N); Lake Dunmore, Aug. 31, 1896, Ezra Braincrd (H); 

 Lake Bomoseen, Castleton, Oct. 1, 1898, W. W. Eggleston (H). 

 Massachusetts: Kenoza Lake, Haverhill, Aug. 10, 1913, J. R. hunt 

 (N); ad Lacum Wenham, Oakes (H); Westford, Aug., 1903, Miss E. 

 F. Fletcher, no. 2 (H); Hagget's Pond, Andover, Aug. 8, 1903, A. S. 

 Pease, no. 2,458 (N); Flax Pond, Lynn, Aug. 22, 1880, E. & C. E. 

 Faxon (H & N); Sluice Pond, Lynn, Aug., 1880, H. A. Young (N); 

 wet shore of Concord River, Concord, Aug. 5, 1886, E. S. Hoar (N); 

 Mystic Pond, Winchester, Aug. 13, 1865, William Boott (H); Fresh 

 Pond, Cambridge, July 1865, Asa Gray (H), July 25, 1879 and July 27, 

 1880, Thomas Morong (N); Cambridge, Nuttall (A); Jamaica Pond, 

 Jamaica Plain, July 13, July 17, Julv 31, Aug. 10, Aug. 18, Aug. 30, 1880, 

 E. & C. E. Faxon (H & N); in a pond, Plymouth, Aug. 26, 1913, 

 S. N. F. Sanford (N); Lake Quinsigamond, Worcester, July 29, 1864, 

 J. W. Robbins (H); ex canali ad Uxbridge, 1849, J. W. Rabbins (H); 



