134 OR. J. W. HESLOP HARBISON ON 



Plantago maiitima o Pallavicinia Flotovviana / 



Erythraea pulchella vr Br3'um spp c 



- — a Florula greatly recalling that of dampish dune hollows. 



VI.— CONCLUSION. 



We are now in a position to review the results of our 

 labours, and to make the desired comparisons with the lists 

 given in Brewster's History of Stockton and Sharp's History 

 of Hartlepool. It is impossible to repeat the latter lists here, 

 and indeed there is no necessity for doing so, so very few of the 

 old specialities in water and marsh plants having died out. In 

 fact, the only absentees worthy of mention are Hottonia 

 pahistris, Pinguicnla vulgaris, Sagittaria sagittifolia, and 

 Butovms iiinbellatus. Of the first three, Sagittaria may yet be 

 reinstated, but I am afraid that the constant clearing of the 

 waterways to secure adequate drainage of the low-lying soils, 

 added to the effect of works, has effectually stamped out the 

 other two ] this is rendered the more probable because all three 

 reach their most northerly habitats on the eastern coasts- 

 Besides, the same plants are extinct in the Middlesbrough 

 Marshes on the Yorkshire side, although there the iron works 

 are the most potent agencies in their suppression. Beyond the 

 boundaries of the industrial area, the nearest station for 

 Hottonia is Stokesley where it revels in old clay holes, but I 

 know of no certain locality for the other two nearer than the, 

 Derwent at Malton. 



Why Pingtiicnla has vanished I cannot pretend to tell. The 

 habitats presented are for the most part quite untouched, and 

 the ground remains precisely like that on which the plant 

 flourishes elsewhere in the county. Still, deliberate searches 

 conducted on my hands and knees to eliminate faulty observa- 

 tion, in the likeliest of localities, have been quite profitless. 

 Thcit its extermination depends on local vicissitudes appears 

 certain, since Pinguiaila grows as freely as one could ever 

 wish to see it on Waldridge Fell, at Wolsingham, Blackball 

 Rocks and in Upper Teesdale — to name only a few of its 

 haunts — and in the first-named conditions are certainly far 



