240 



J. O. HAGSTROM, CRITICAL RESEARCHES 0> T THE POTAMOGETONS. 



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

 to be found in Raunkler, Anat. Pot. Stud., 1903. 273, f. 8. 



To judge from its description P. Noltei [i Harzii Fisch. is a somewhat dubious 

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

 sicher P. lucens x vätans ond sollen den Namen P. Harzii trägen» (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 ,3 rivularis Lange 

 from Fyen is the hybrid P. spar- 

 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 Baagöe in 

 Asch. & Gr.ebner, Synopsis, is the 

 hybrid lucens x natans according to 

 specimens from the author himself; 

 8 sublucens Baagöe, 1. c, is P. sub- 

 rufus, see below! 



Distribution: Sweden, Scania, 

 Vegeholm, 81, Wallengben (hb. 

 Stockholm.); Helgeå, Ahnfelt (hb. 

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



Fig. 112. P. lueens X naton$ <P. alerilla Haosts.). A, B, C, Difiér- fluitans. — Smulaud, »GllillingC ma- 

 • ■nt forras of tl(j;itinf; leaves, C. more rare and otterly like a leaf of /'. , . ^ . , „_. TT ., ■ 



tparffanifMut, j. of. Bg. 104. der» near Vrigstad, 93, Hamner (hb. 



Stockholm.). — Upland, Svartsjölan- 

 det »Vänt holmen väster om Norrskog i Kronängens dike», 4G, Lagerheim and othcrs 

 (hb. Stockholm., Uppsal., Lund., Gothenb.) in hb. E. Fries, named by himself »7\ 

 fluitans Roth»; Vallstanäs, in cffluvio lacus Fysingen, 87, Tiselius (hb. Stockholm., 

 Uppsal., Lund.). 



Denmark, Jutland, Vardeå, 95, Ostenkeld-Hansen and othcrs (hb. Stockholm., 

 Lund.); Gudeni, 95, Baagöe (hb. Uppsal.); Skierna, 9.">, BAAGÖE (hb. Hagström): 

 Vardeå, 99, Baagöe (hb. Eaostb.); Skalså, 04, Baagöe (hb. Hagstb.); Fyen, 

 Odenseå, 97, Baagöe (hb. Hagstb.). — Qermcmy, »Oldcslo nicht fern von Liibeok, 

 NOLTE» (hb. Stockholm.); llolsati;i>, NoLTE (hb. Stockholm.); »fl. shl» (hb. Stock- 



