184 J. O. HAGSTRÖM, CR1TICAL RKSEARCHES ON THE rOTAMOGETONS. 



P. canariensis Link in Buch, Beschreib. Canar. Inseln, 1825, 138. — P. Leschenaullii 

 Cham. & Schlbcht. in Linnea, 1827, 223? — P. occidentalis Sikher ap. Cham. & Sciil., 

 1. c. 224. — P. americanns Cham. et Sciil., 1. c, 226. — P. syriacus Cham. & Schl., 

 1. c, 227. — P. mascarensis, P. marianensis, and P. owaihiensis Cham. & Schl., 



I. c, 228. — P. petioiatus Wolfo. ap. SchultEs, Mantissa in vol. III etc, 1827, 252. — 

 P. Roxburghianus Sciiultes, 1. c, 367? — P. Besseri Steudel, Nomenclator ed. 2, 



II, 1841, 384? — P. Billotii Sciiultz, Archives de la Fl. de France et d'Allem., I, 

 1842, 61. — P. lonchitis Tuckerm., Observations etc. in The Am. Journ. Sci. and 

 Arts, 1848, 226. — P. fluitans (Roth) Raunkler, Anatom. Pot. Studies etc. in Rot. 

 Tidskr. 1903, 271—280. — Fig. 1, C, 95. 



By the earlier authors, Koch, Gaudfn etc, and quite up to låter times (Bfche- 

 nau), this species has been mixed up with P. notans L., and placcd as a varietv under 

 that species (P. natans p explanatus Mert. & Koch, 1823, 837 — 838, etc). Other 

 authors, separating it true enough from P. natans, have commingled it with so me 

 hybrids under the name of P. fluitans Roth. Thus P. Graebnkr. who, although 

 distinguishing between fruiting and sterile forms, yet looks upon them all as »einheit- 

 liches Ganzes» (Lebensgesch. etc. 1906, 435; so still in Synopsis, 1912, 464 sq.) 

 possibly of hybrid origin. With this view the name P. fluitans can be said to be 

 the only correct name for those forms. C. Rafnkler has by means of specimens 

 determined by Roth tried to prove that the name P. fluitans only is due to the 

 fruiting plant, which under a great number of names, but first by Poiret, has been 

 described. This proof would be very strong, if those specimens examined also really 

 corresponded with the original description by Roth »foliis inferioribus longissimis» 

 etc. (Tentam. Fl. Germ. I, 1788, 72), which they can scarcely be said to do. Nor 

 has Raunkler tried to show that. Rather this description answers to the hybrid 

 lucens X natans, which more of ten than P. nodosus has very long and always morc 

 durable submersed leaves. Only in very rare cases P. nodosus has leaves of a foot- 

 longth or morc Stränge to say G. Fisciier, however, finds this description adequate 

 to the fruiting plant when writing, »Wäre nur die erste Publikation Roth\s v. .1. 1788 

 vorhanden, so wiirde ich nicht das mindeste Bedenken trägen, der Art den Nameu 

 P. fluitans Roth zu belassen. Denn die kurze Beschroibung stimmt da/.u.» On the 

 other hand the same author is of the opinion that Roth's second and more detailed 

 description contains more characteristics not at all agreeing with the plant, looked 

 upon as a true species, but refcrable to a hybrid. FlSOHER, thcrefore, writos in 

 l!)()7, /'. fluitans (Roth? Rchb. p. p.) Kocn, s. str. F. », a mode of signifying, which, 

 probably, w ill not gain adherence. Seven yeara låter ho writes: /'. fluitans Roth, 

 and divides it into two parts: Protes (vel sectio, serie*) I. /'. Rothii FlSOHER, and 

 Protes (vol sectio, series) II. /'. Raunkiceri Fisgher, the latter > P. natans X lucens 

 sec. Raunk., 1 1 aostr. »' (Bemerkk. zu den PotamogetonesB etc in .Milt. Bayer. B. 

 Ges. I!)14). Farther below, on the same page, he notes, »Meine Vollmannsdorfer 

 Exemplare Bind sicher /'. lucens X natans and sollen den Xamen /'. Harzii 



1 Rauhkj/EH ;iimI ll\'i iit"M write /'. Innu natans. 



