KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 55. N:0 5. 185 



trägen». This name is earlier used of a f. pernatans of P. Noltei Fisch. and to it can- 

 not further be attributed the sense of a name for the hybrid P. lucens X natans in the 

 main, and the name >P. Raunkiceri* is strictly to be written P. flintans Rth proles 

 Raunlciceri Fischer, which designation means all forms of »P. fluitans» referable to 

 the »hybrid fluitans». Consequently, with the great abundance of names, we still do 

 not possess a specific name for the bastard we call P. lucens L. X natans L. 



Fischer has found a support for the maintenance of Roth's name in the fact 

 that, both of old and in låter times, P. nodosus has been gathered in the Hunte 

 River, the station recorded by Roth for his P. fluitans (Fischer, Beitrag z. Kennt- 

 niss bayer. Pot. IV, 362, and Die bayer. Potam. 1907, 143). It must be admitted 

 that, if the Hunte were the sole locality recorded by Roth, the occurrence of P. 

 nodosus there now-a-days would be an important instance for the name question, 

 but Roth's note of the locality originally runs thus: »Hab. in fossis profundis lente 

 fluentibus et in Hunte fluvio» etc, which evidently shows that Roth with his 

 description has also had in view other forms than the plant of the Hunte River. 

 To me the fact is conclusive that Roth, in his original description, states nothing 

 separating the fruiting plant from similar bastard plants found in the same region. 

 On account of this circumstance the name P. fluitans has been used, by different 

 authors, with just the same right, now in one, now in another sense. The confusion 

 and fluetuation have also increased by the fact that we have at least five hybrids 

 (or more, if we count the extra-European forms) corresponding to the description of 

 P. fluitans, viz. beside the rather commonly acknowledged P. lucens X natans, also 

 natans X nodosus, natans X polygonifolius, lucens x nodosus, gramineus X natans, i. e. 

 almost all watott s-hybrids, which are endowed with very long submersed leaves. If 

 we, therefore, wish to avoid a fruitless contest on a name to the end of the days 

 I am able to see only two ways out: one, with Ascherson and Graebner, to join 

 all forms answering to the description into a unity, P. fluitans Roth, without discri- 

 mination, which must be rejected as leading into a chaos, the other, with disapproval 

 of that vague (»floating») name, to separate the different forms after their essential 

 characteristics, giving them names, if not already done. Concerning the fruiting 

 European plant (the »fertile fluitans >) it does not stånd in need of name, as it, on 

 the contrary, has a great abundance thereof (see above!). The oldest I have been 

 able to trace out is the above-cited by Poiret, whose description, after specimens 

 from Broussonet, of the Canary Islands, undoubtedly is referable to our species, 

 which fact is also confirmed by the fruit-description, made by Chamisso and Schlech- 

 tendal in Linnsea in 1827, p. 223, Tab. IV, f. 22. Many j^ears ago I have suggested 

 this good name to be adopted. The species is indeed nodosus, as the submersed leaves 

 soon decay, making the nodes appear more obviously than other wise. 



Respecting the origin of the fluitans-iorms of which some authors have written, 

 we well know that of the bastards mentioned above. P. nodosus, again, is thought 

 to be a variety of P. natans (Buchenau) or a developmental stage of a primordial 

 bastard (Graebner). Fischer writes (1904): »Vielleicht ist der fertile und der sterile 

 Form P. fluitans doch auf einen gemeinsamen Typus öder Stamm zuruckzufiihren 



K. Sv. Vet. Akad. Handl. Band 55. N:o 5. 24 



