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



263 



P. (liniorphns Raf. x pusillus L. (P. dimorphoides n. hybr.). 



Pot. ad ramificationem P. dimorpho similis. Pedunculi elongati ut in P. pu- 

 sillo. Folia omnia submersa forma structuraque intermedia. 



The ramification of this plant is like that of P. dimorphus. Leaves interme- 

 diate. Lateral nerves very faint. Ligules open, 6-fibrous in the front-field. Pedunc- 

 les like those of P. pusillus. Spikes small. — Gathered by T. Morong, 81 (hb. 

 Haun.). 



As to the distribution of P. gramineus X natans (p. 219) two more localities 

 may be added, viz. Norway: Senjen isl., 63, Norman, 10, Notö (hb. Christian.), and 

 Hvalöerne: Kirkeö at Böbakke, 42, Printz (hb. Christ.). — 



P. nericius (p. 145) occurs in Iceland, Reykhult, 76, Grönlund, Reykjavik, 

 95, Ostenfeld Hansen (hb. Haun.). 



P. Torssandri (p. 216) has been gathered in Norway, Frosta, Liavand, 14, b}^ 



I. JÖRSTAD. — 



The most northern habitat of P. polygonifolius Pourr. hitherto known is Vest- 

 vågöen in Norway, where it has been gathered by J. M. Norman in 1878 (hb. 

 Christian.) — 



I will lastly give a brief summary of the groups and the number of the spe- 

 cies and hybrids belonging to each of them: 



Groups 



Species i Hybrids 



Groups 



Species 



Hybrids 



1. Filiformes . . 



2. Amblyophylli . 



3. Vaginati . . . 



4. Pectinati . . . 

 P. Livingstonei 



5. Serrulati . . . 



6. Crispi . . . . 



7. Compressi . . 



8. Monogyni . . 



9. Ochreati . . . 



10. Polygoni . . . 



11. Oxyphylli . . . 



12. Monticoli . . . 



13. Pusilli . . . . 

 P. uruguayens is 



4 

 1 

 3 



o 





1 



1 



1 



— 



2 



1 



1 



3 



2 



2 



1 



1 



2 



— 



3 



— 



5 



1 



19 



— 



14 



1 



— 



14. 

 15. 

 16. 



17. 



18. 



19. 



20. 



21. 



22. 



23. 



24. 



25 



26. 



T. Curtissii . 



Javauici . . 



Hybridi . . 



Alpini . . . 

 Amplifolii 

 P. Thunbergii 



Muricati . . 

 Sclerocarpi 



Colorati . . 



Notlosi . . 



Natantes . . 



Lucentes . . 



Praelongi . . 

 Perfoliati . 



Densi . . . 



1 

 9 

 6 

 o 



90 



1 



8 

 7 

 6 

 1 

 4 

 19 

 1 



o 

 O 



2 

 2 

 3 



17 



1 



