1916] St. John, — Potamogeton, Section Coleophylli 133 



KEEWATIN: Cape Henrietta Maria, Hudson Bay, Aug. 14, 1904, 

 W. Spreadborough, (C no. 62,660); Churchill, Hudson Bav, Lat. 58° 

 50', Aug. 3, 1910, ./. M. Macoun, (C no. 79,199 & H).' Quebec: 

 St. John (or Douglastown) River, Gaspe County, Aug. 23, 1904, 

 J. F. Collins, M. L. Fernald, & A. S. Pease (C & H). Vermont: 

 shallow hay south of "Carry," North Hero, Aug. 2, 1899, Ezra Brain- 

 erd (H). Nevada: Ruhy Lake, alt. 6,000 feet, Aug., 1808, Sereno 

 Watson, no. 1,143 (H & Y). Alaska: shallow pools, St. Paul Island, 

 Bering Sea, July 15, 1897, J. .V. Macoun, (C no. 28,158). 



Several recent European workers have subdivided this species into 

 varieties or forms. 1 A tall coarse plant with leaves over 1 mm. in 

 breadth is treated as var. alpinm (Blytt) Asch. & Graeb. This 

 variety seems to be quite distinct. The species has been further 

 divided on the basis of the overtopping of the spikes by the leaves or 

 the reverse and the elongation or dwarfing of the stem, making a 

 series of four forms or varieties. The variation in these parts seems to 

 be due mainly to the fluctuations in the water level and to be negli- 

 gible from our standpoint. All of the European specimens of P. fili- 

 formis Pers. and its varieties are characterized by having an elongate 

 spike formed of mostly remote whorls. 



For many years this plant was treated as P. marinus L. This 

 Linnean species is very difficult to interpret with any surety on the 

 basis of its description in the Species Plantarum or the sources cited 

 there. A. Bennett discussed the basis of P. . •ariuus in 1890 2 and 

 again in 1895 3 concluding that " Most European authors use the name 

 P. marinus Linn. In the Linnean Herbarium the specimens named 

 ■mar in as are only pectinatus" ; and, following Bennett, the name P. 

 fUiformis has been almost universally adopted for the plant under 

 discussion. A most disconcerting discovery is that Bennett himself 

 in his most recent work has reverted to the name P. marinus.* In 

 reply to my request for an explanation of this change Mr. Bennett 

 dwells on the- pre-Linnaean sources cited in the Species Plantarum, 

 especially Boccone, Icones ct Dcscrip. PI. Siciliae, 42, and t. 20, f. 5 

 (1674) He concludes that, " This drawing might well have been made 

 for a species of P. fasciculatus of Wolfgang, which is only a small 

 filiform is!" Mr. Bennett is quite correct in saying that Boccone's 

 Potamogeiton pusillum fluitans might be some phase of the plant we 



1 Hagstrom in Neuman, Svoriges Flora, 794 (1901); Ascheraon iV Graebner, I. c : Fischer, 

 1. c. 



- Bennett, Journ. Bot. xxviii. 301 (1890). 



3 Bennett, Bull. Herb. Hoissier iii. 257 (1895). 



« Bennett in Fryer, I. c. 89 (1915). 



