TOPOGRAPHY AND PHYSICAL GEOGRAPHY. 125 



characteristically maritime plants. The coast cliffs yield very 

 few and the only tract where they grow in any considerable 

 abundance is the sweep of low marshland which borders the sea 

 in the neighbourhood of Middlesbrough and Coatham. 



4. The Hygrophilous Species or plants of standing water. 

 These are the lacustral or paludal plants of the low country, none 

 having been included here which ascend into the Middle Zone. 

 Though the total number of species which it includes is not 

 conspicuously small, the North Yorkshire flora cannot be said to 

 have a large infusion of this element, but rather the reverse. 

 Many of the species are restricted to two, three, or four of the 

 drainage districts. 



5. The General Ascending Species, i.e., those which are ascer- 

 tamed to occur in all the nine drainage districts. As a general 

 rule the plants which range here are both commoner and more 

 abundant where they occur, not only for North Yorkshire as a 

 whole but also for each of the districts taken separately, than 

 are those of any of the other categories. 



6. The Scattered Ascetiding Species, those which do not range 

 under any of the preceding categories and which are ascertained 

 to occur in not less than four of the drainage districts. Some 

 of theericetaland shade-loving plants which are plentiful amongst 

 the hills come in here, and no doubt many species which further 

 observation will shew to be really ' General.' 



7. IVie Local Ascending Species, those which do not range 

 under any of the preceding categories and are ascertained to 

 occur only in from one to three of the drainage districts. 



The following table shews for North Yorkshire as a whole 

 the absolute number of the Native Flowering Plants and 

 Ferns of each of these categories in its flora and the relative 

 proportion which each bears to the whole flora as tested by 

 the number of species. 



July 1888, 



