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NOTES ON THE VEGETATION OF PONDS. 



WILLIAM G. SMITH, B.Sc. Ph.D., 

 Yorkshire College, Leeds. 



The veg-etation of a number of small ponds near Filey was 

 a feature of the botanical excursion at the Y.N.U. meeting on 

 Whit-Monday last. Almost the first pond met with was re- 

 splendent with a mass of Bog-bean in flower, and, as one after 

 another pond was visited, it became evident that each had 

 features peculiar to itself and was quite distinct from any of its 

 neighbours. This we have endeavoured to show by means of 

 the three diagrams reproduced. They are prepared from free- 

 hand sketches of three distinct ponds, and the arrangement of 

 the vegetation is given as nearly as possible. The diagrams 

 and notes are given here, not as a complete study, but as the 

 result of a single day's excursion. Yet they show points of 

 distinct interest in the distribution of plants, and will have 

 served their purpose if they only show what an excellent 

 opportunity for local survey lies to the hand of those who can 

 make continued observations on these or similar ponds. 



The ponds are situated on uncultivated land about two miles 

 south of Filey, and are all within a quarter of a mile from the 

 edge of the boulder clay cliffs. The land surface is irregular 

 and made up of a series of knolls and ridges, with hollows or 

 troughs between, which lie approximately parallel to the cliff 

 edge. In many of these troughs ponds of various sizes have 

 formed. The three shown in the diagrams are about the same 

 size, roughly about sixty yards long, and like most of their 

 neighbours they are long oval in shape. Their features are 

 best dealt with by taking them one after another. 



Fig. I. — This may be distinguished as the Bog-bean pond 

 from the great abundance of Menyanthes trifoliata. It is an 

 example of the pond with open water, a few of which were seen, 

 and one in particular had only a narrow belt of marginal plants. 

 The Bog-bean pond occupies a hollow near the cliff edge, from 

 which it is separated by a single ridge only, so that it may soon 

 share the fate of an adjacent pond, the outer containing ridge 

 of which has already gone over the cliff. An outflow channel 

 is shown at the southern end, but this lies so high that it can 

 only serve as an overflow channel when the pond becomes full 

 of water. When the water begins to escape by this overflow- 

 outflow the pond will have reached its maximum depth, as was 



1903 October i. 



