Former Distribution of British Plants. 155 



POTAMOGETON NATANS, L. 

 Neolithic : — 



Drope, Glamorgan. 



Late Glacial : — 



Ballaugh, Isle of Man (bed F). 

 Interglacial : — 



West Wittering, Sussex. 



Also recorded from Klinge bei Cottbus, in Prussia ; 

 Fahrenkrug in Holstein \ Honerdingen, in Hanover (Carl 

 Weber) ; and from the Birch, Pine, and Oak Zones in 

 Sweden (Gunnar Andersson). 



POTAMOGETON RUFESCENS, Schrad. 



Late Glacial : — 



Twickenham, Middlesex ; Hoxne, Suffolk (bed C). 



Interglacial : — 



Kilmaurs, Ayrshire (?) (Bennett). 



Also recorded from Honerdingen, in Hanover, asso- 

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



POTAMOGETON HETEROPHYLLUS, Schreb. 

 Neolithic : — 



Drope, Glamorgan ; Hailes, near Edinburgh. 



Interglacial : — 



West Wittering, Sussex ; Stone, Hampshire ; South- 

 elmham, Suffolk; Kilmaurs, Ayrshire (or P. Zizii) 

 (Bennett). 



Preglacial (Cromer Forest-bed) :— 

 Abundant at most localities. 



