Estuarine Plants 233 



There yet remains one group of plants, the estuarine flora, 

 of which hitherto no mention has been made. 



Originally a large portion of the fens must have been 

 under the influence of the tide. Until the two great cuts, 

 the old and new Bedford rivers, were made and Denver sluice 

 erected, the tide flowed up the Cam to within ten miles of 

 Cambridge. Now the salt water is diverted and flows up 

 the New Bedford river, ordinarily beyond Welney, and at 

 spring tides as far as Mepal. A fresh-water tide is felt 

 however beyond Earith. 



These great drains are very difficult of access, roads are 

 scarce and convenient railway stations still scarcer. It is 

 nevertheless comparatively simple to approach them at Earith, 

 where is the junction with the Ouse, at Mepal, at Welney, 

 and again by train at Downham Market, where they again join 

 the river. 



The estuarine plants are however not abundant and are, as 

 would be expected, for the most part near Downham Market. 



The following short list probably includes the greater 

 number of those to be found. 



Cochlearia anglica. 

 Aster tripolium. 

 Scirpus maritimus. 

 Glyceria maritima. 



How far these extend up the New Bedford River has not 

 been ascertained. They were with the exception of Scirpus 

 maritimus noticed by Denver sluice. The Scirpus is probably 

 to be found at Welney. 



Traces of old tidal influence are very rare. Apium graveo- 

 lens in its more northern localities may be due to this, and 

 Scirpus maritimus at Littleport, where it still exists or did till 

 comparatively recently, is another example of an old estuarine 

 flora. 



There are besides these two species two more, Viola 

 lutea and Bupleurum tenuissimum ; the first in West Suffolk, 



