76 



Bennett: Notes on the Potamogetons. 



Is P. pectinatns L. f. pseudo-mariniis Ar.Benn. = f. salina 

 Voch. 



There is a record oi P. acutifoliiis Link in Mr. H. H. Slater's 

 'Flora of Ripon,' 1873; but Dr. F. A. Lees, in his 'Flora of 

 West Yorkshire,' says, ' Should be looked for, very doubtful.' 



I may here correct an error in the ' Flora of Skipton,' p. 38, 

 1900. P. prcelongus Wulf is there recorded from the ' Canal at 

 West Marton.' I asked Mr. Rotheray to kindly send me the 

 specimens, and they proved to be P. perfoliatiis L. I was much 

 disappointed, as the species seems to be very rare in Yorkshire. 

 Mr. Watson queried both V.C. 62 and 63, and gave 64 as an 

 error.'-'' But Mr. Backhouse recorded it from Malham Tarn as 

 found on the nth of July 1844. ' A high wind ruffled the waters 

 of the tarn, and brought considerable quantities of Potamogeton 

 liicens, perfoliatns, 2,\\di pra'longiis to the shore.' Phyt. , Vol. L, 

 p. 1 1 26, November 1844. This is the only station in the county 

 I have seen specimens from. Mr. Baker has no record in North 

 Yorkshire, saying, p. 385, ' The Gormire plant is erroneously 

 given prcElongus in Supp. Fl. Yorksh.' It is an early flowerer 

 (May and June), and then sinks to mature its fruit ; and in July 

 and August must be 'dragged' for in deep water. 



In the Comp. Cyb. Britt. , p. 344, Watson says prcelongus y 

 ' Low grounds' ; yet in the Cyb. Britt., Vol. III., he says, 'the 

 altitude of that tarn (Malham) is said to exceed 1,200 feet.' Of 

 late years it has been gathered at 2,500 feet near Killen, Perth 

 (Macvicar sp., 1893), and from Meall nan Tarmachan, Perth, 

 at 2,500-3,000 feet (Messrs. Dixon and Valance sp.). 



Although now generally accepted as two species P. zosteri- 

 foliiis and acutifoliiis were formerly made one species (i.e., by 

 Roemer and Schultes, Mant. V., III., Sys. Veg., p. 362, 1827). 

 No two species could be more unlike in constitution (if I may 

 use the word), acutifolius is an early flowerer, often in the first 

 week in June with well-formed fruits, rarely at this time with 

 barren stems, while the other is a late flow-erer (July and August) 

 and with abundant barren stems. There are very few good 

 figures of the fruit of acutifolius ; the best is Reichenbach's in 

 his Fl. German et Helv., Vol. VII., 1845. The length of the 

 peduncles in this must not be relied on too much ; I have seen 

 French specimens \\\\.\\ these i inch in length, and a variety 

 from Mandshuria with them 1^4 inches long. 



• Vet in Cyb. Britt., Vol. III., 17, 1852, accepted it. 



Naturalist^ 



