156 Origin of the British Flora. 



POTAMOGETON LUCENS, L. 

 Neolithic : — 



Cowden Glen, Renfrewshire. 



Interglacial : — 



West Wittering, Sussex. 



Preglacial (Cromer Forest-bed) : — 



Between Cromer and Runton, in Norfolk ; Corton, 

 Pakefield, in Suffolk. 



POTAMOGETON PR/ELONGUS, Wulf. 

 Neolithic : — 



Megaceros-marls of Central Ireland. 



Preglacial (Cromer Forest-bed) : — 



Between Cromer and Runton. 



Recorded from the Dryas, Birch, and Pine Zones (Late 

 Glacial and Neolithic) in Sweden (Gunnar Andersson); 

 and with doubt from Honerdingen, in Hanover, with 

 Juglans, Platanus, &c. (Carl Weber). 



POTAMOGETON PERFOLIATUS, L. 



Neolithic : — 



Redhall, near Edinburgh ; Hailes, near Edinburgh ; 

 Cowden Glen, Renfrewshire. 



Interglacial : — 



Southelmham, Suffolk. 



Also recorded from Honerdingen, in Hanover, asso- 

 ciated with Juglans, Platanus, &c. (Carl Weber). 



POTAMOGETON CRISPUS, L. 

 Neolithic : — 



Gayfield, near Edinburgh; Megaceros-marls of Central 

 Ireland. 



