23O HULL SCIENTIFIC AND FIELD NATURALISTS CLUB. 



of plateaux of almost uniform height. The one at Saltend 

 is about 12 ft. O.D.; that along Cherry Cob Sands averages 

 12 5 ft. O.D.; and the one immediately east of Stone Creek 

 is about 13 ft. O.D. These can hardly be classed as salt- 

 marsh, since they are quite dry, except at the higher spring 

 tides. At lower levels, there are only the banks of three 

 creeks and the salt-marsh of Sunk Island and Welwick. 



The distribution of plants on these plateaux is no doubt 

 influenced by the grazing of horses and cattle, and the 

 absence of a particular species on any one of them may be 

 due to other reasons than the varying periods for which they 

 are submerged. This remains to be determined ; at present 

 I can only give a few facts on the range of particular species. 

 The range of the tides must, of course, be taken into account 

 in comparing the situations given with other localities. 



Aster Tripolium grows from 6*5 ft. O.D., the outer edge 

 of the salt-marsh, to about 1 1 "5 ft. O.D. Its upper limit is 

 uncertain, as it is eaten off by cattle. Dwarf specimens 

 occur on the higher levels with flowering shoots about six 

 inches high ; some have evidently been cropped short, but 

 others appear to have withered at the top without any previous 

 mutilation. Further facts about this plant and Statice will be 

 given later. 



Obione portulacoides flourishes over the whole area, except 

 perhaps in the highest and lowest foot. It is common on the 

 Welwick and Sunk Island salt-marsh, and is fairly abundant 

 on the Cherry Cob Sands plateau. It seems to survive, 

 enclosure for about six years. Thrift is more abundant on 

 the Saltend plateau (12 ft. O.D.) than on the other 

 two. Artemisia maritima does not grow below 13 ft. 

 O.D., almost at the upper limit of spring tides. This 

 usually confines it to the slope of the bank, though it also 

 occurs on the higher parts of the plateau at Cherry Cob 

 Sands. The lower leaves appear to be killed by the salt 

 water. 



Biipleuram tenuissimum grows with Artemisia at 13 ft. 

 O.D., but never away from the bank. It may be found all 

 along from Saltend to Welwick, 2 ft. high when growing 

 amongst long grass on the Hedon Haven bank, or barely 

 6 inches in more exposed positions. 



Trifolium fragiferum commences at 13 ft. O.D. , where it 

 is submerged at the highest spring tides, and continues to 

 the top of the bank. 



Plantago maritima and Triglochin maritinuim appear to 

 flourish best at 10-12 ft. O.D. 



