240 



J. O. HAGSTEOM, CRITICAL RESEARCHES ON THE POTAMOGETONS. 



P. sterilis is figured in Flora Danica t. 2105 (1834); cross-section of stem is 

 to be found in Raunki^r, Anat. Pot. Stud., 1903, 273, f. 8. 



To judge from its description P. Noltei [3 Harzii FisCH. is a somewhat dubious 

 plant to me, although the author writes: — »Meine VoUmannsdorfer Exemplare sind 

 sicher P. lucens X nutans und sollen den Namen P. Harzii tragen» (FiscH., Bemerkk. 

 1914). The very short internodes, short ligules and leaves, and the slight cusp of 

 the floating leaves with roundish bases seem to me to remind of another hybrid. 

 As to the name P. Harzii I think it incorrect to give to a hybrid with its 



many forms the same name as has 

 already been used of a particular 

 form of the hybrid concerned. (Vide 

 The International rules. Art. 4:2: 

 avoidance of ambiguity and con- 

 fusion). 



P. fluitans p rivularis Lange 

 from Fyen is the hybrid P. S2Mr- 

 ganifolius according to specimens of 

 the year 1847, gathered and named 

 by Lange himself (see p. 219!). 

 But I have seen true P. sterilis also 

 from the same river (Odenseaa). — 

 P. fluitans a. typicus Baagoe in 

 AscH. & Greener, Synopsis, is the 

 hybrid lucens X nutans according to 

 specimens from the author himself; 

 8 suhlucens Baagoe, 1. c, is P. sub- 

 rufus, see below! 



Distribution: Sweden, Scania, 

 Vegeholm, 81, Wallengren (lib. 

 Stockholm.); Helgea, Ahnfelt (hb. 

 Uppsal.) ex hb. E. Fries, lab.: P. 



Fig. 112. P. lueensXnatans (P. stei-ilis YiKasm.). A, B, C, TiiSev- fluitanS. — Smolund, jGnillingema- 

 ent forms of floating leaves, C, more rare and utterly lilce a leaf of P. , tt ■ ; n <-,r. -tt /i i 



spm-ffanifoiius, {. cf. fig. 104. der» near Vrigstad, 93, Hamtster (hb. 



Stockholm.). ■ — Upland, Svartsjolan- 

 det »Vantholmen vaster om Norrskog i Kronangens dike», 46, Lagerheim and others 

 (hb. Stockholm., Uppsal., Lund., Gothenb.) in hb. E. Fries, named by himself »P. 

 fluitans Roth»; Vallstanas, in effluvio lacus Fysingen, 87, Tiselius (hb. Stockholm., 

 Uppsal., Lund.). 



Denmark, Jutland, Vardea, 95, Ostenfeld-Hansen and others (hb. Stockholm., 

 Lund.); Gudena, 95, Baagoe (hb. Uppsal.); Skierna, 95, Baagoe (hb. Hagstrom); 

 Vardea, 99, Baagoe (hb. Hagstr.); Skalsa, 04, Baagoe (hb. Hagstr.); Fyen, 

 Odensea, 97, Baagoe (hb. Hagstr.). — Germany, »01deslo nicht fern von Liibeck, 

 NoLTE* (hb. Stockholm.); Holsatiae, Nolte (hb. Stockholm.); »fl. shl» (hb. Stock- 



