NOTES ON POTAMOGETON 375 



reverse be pleaded ? — nutans as a higher form of polygon if oliiis. 

 Again, altitude is suggested as making some modification; certainly 

 it does to some extent, especially if in shallow water, but I have 

 P. nutans from India from 9000 ft. altitude (Duthie) indistinguish- 

 able from Surrey specimens ; and so with other specimens. 



P. ochreatus Raoul ! in Ann. Sc. Nat. ser. 3, ii. 117 (1844), 



and Choix, PL Nouv. Zel. 13 (1846). 

 P. gramineum E. Brown! Prodr. FL N. Holl. 343 (1810), 



non L. 



P. obtusifolius Bentham ! FL Austral, vii. 172 (1878). 



A form (latifolius) of this species occurs in the Murray River, 

 South Australia (leg. Tepper), with leaves double the normal width, 

 1 dm. long, and with forty-five nerves or veins." None of the 

 New Zealand specimens approach this, nor do the Centinneal Park 

 specimens, N.S.W. Australia (leg. Maiden), though larger in all 

 parts than most examples of the species. 



In habit the species is variable; specimens from Australia 

 Felix (F. v. Mueller) are straggling in growth, while those from 

 the Yarrogobilly River, N. S.W. Australia (ex Maiden) have shorter 

 internodes with fascicles of leaves in the leaf-axils ; peduncles 

 2| cm. long ; spikes 1J cm. Others from the Waihi Stream, North 

 Island, New Zealand (leg. Cheeseman), have long internodes, no 

 fascicles of leaves, and peduncles 1 dm. long, and spikes 2^ cm. 

 long ; and Moreton Bay examples come between these. 



Raoul's description was made from specimens from the Banksian 

 Peninsula, New Zealand. 



Additional Australian stations to those given by authors will 

 be found in the First Government Report (1853), by F. v. Mueller, 

 p. 30. 



X P. venustus Baagoe in Actes Congr. Internat. Bot. Paris, 

 1900, p. 516 (P. alpinus Balb. x P. crispus L.). Hab. in parte 

 amnis " Gudemi " qui Lillea vocatur Jyllandia, 1899; in rivulis 

 "Vigersdala," Saellandie, 1899. 



For specimens of this remarkable plant I am indebted to the 

 late Mr. Baagoe, of Naerstad, Denmark. The habit is that of 

 alpinus, but with the nervation nearer crispus ; the leaves are not 

 serrated, the peduncles and spikes are those of aljnnus, and the 

 upper leaves are suffused with red in the same way ; the stems are 

 also compressed, though in a less degree than in crispus. 



Though quite willing to question its hybrid origin, I do not 

 see how to avoid that conclusion ; the plant cannot be placed with 

 either crispus or alpinus, and I am not prepared to suggest it as a 



new species, as the condition of the spikes suggests hybridity. 



X P. ripen sis Baagoe in /. c. (P. zosterifolius Schum. x tfi- 

 choides Cham.). Distributed by Mr. Baagoe as P. zosterifolius 

 Schum. f. gracilis. Hab. in amne Nibsa, prope Ribe, Jyllandia, 

 Denmark, 1899. 



I accept this name on Mr. Baagoe's authority. There are no 



In original examples (ley. Raoul) the veins are thirty to thirty-five. 



