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 PRALONGUS, 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 /uglans, Platanus, &c. (Carl Weber), 
POTAMOGETON CRISPUS, L. 
Neolithic :— 
Gayfield, near Edinburgh; Megaceros-marls of Central 
Treland. 
