NOTES ON POTAMOGETON 373 



Two distinct forms, therefore, have been tentatively referred to 

 S. volubile, and it remains for further investigation to decide which, 

 if either, of these determinations is correct. Dudresnaya is not 

 difficult to obtain in certain localities on the south coast, and 

 Strebloncma, when present, is readily recognized by the brown 

 coloration formed in the Dudresnaya fronds. 



NOTES ON POTAMOGETON. 



By Arthur Bennett. 



Potamogeton floridanus Small, Fl. S. E. United States, 37 

 (1903). The following note by Dr. Morong (Bull. Torrey Bot. 

 Club, xiii. 145(1886)) applies, I believe, to this plant: — "Mr. 

 Curtiss also sent what appears to be a peculiar form of P. nutans. 

 It has small, acute, elliptical leaves, 4-6 cm. long by 5-15 mm. 

 wide, and erect peduncles about 6 cm. long. It looks exactly like 

 specimens in the Torrey Herb, from India, which are labelled 

 P. natans, var." The above note is appended to a description of 

 P. Curtissii Morong from the Blackwater River, the habitat of 

 Dr. Small's species. I have little doubt that Dr. Morong's and 

 Dr. Small's are the same species, and I think it likely it may be 

 my P. Teppcri (Journ. Bot. 1887, 178), which lias much the facies 

 of a small natans, and is often so named. If the Torrey Herbarium 

 specimen is from the "Khasia Hills, alt. 4-5000 ft.," collected by 

 Hooker and Thomson, it is P. Tepperi, which at present is re- 

 corded only from Asia and Australia. 



Altitudes of Potamogetons. — The following list of altitudes 



of various species is a contribution to a subject that is little 

 attended to in the genus. In all cases I have seen specimens, 

 with the exception of those of the Geol. Exped. 40th Parallel, 

 Botany, 1871, Washington : — 



P. natans L. Britain, 2500 ft.; Turkestan, 6000 ft.; India, 



9000 ft. ; California, 6000 ft. 



P. polycjonifolius. Britain, 2200 ft. 



P. americanus Cham. Nevada, U.S.A., 6000 ft. 



P. Tepperi A. Benn. Khasia (India), 4-6000 ft. 



P. flnitans Roth. Sikkim (India), 9000 ft. 



P. indie us Roxb. India, 1-7000 ft. 



P. Cheesemanii A. Benn. New Zealand, 2500 ft. 



P. lucens L. Britain, 1100 ft.; Spain, 9750 ft. India: Kumoan, 

 6400 ft. ; Kashmir, 5-6000 ft. 



P. pmlongus Wulf. Britain, 2500 ft. ; France, 1730-2690 ft. 

 Jura, 3500-3800 ft. ; Switzerland, 6500 ft. 



P. cmgustifoliits Bertch & Presl. India : Kashmir, 5150 ft. 

 Himalayas, 6400 ft. 



P. heterophil llus Schreh. Britain, 1600-2300 ft. U.S.A. 

 Montana, 7500 ft. ; Utah, 10,000 ft. 



