46 FLORA OF BRITAIN. 



But many obvious and important peculiarities of plants 

 being altogether unheeded in botanical classification, or 

 at least not allowed to interfere materially with it, the 

 general character of a flora is incompletely shown by re- 

 ference to orders and genera alone. Still less can such a 

 test give any just idea of the floral landscape or physio- 

 gnomy of vegetation, since this depends much more on 

 the prevalence of particular species, in respect to the 

 number and magnitude of individual specimens, than on 

 the number of species referred to any particular order or 

 genus. Thus the genera Corylus, Calluna, Bellis, and 

 Anthoxanthum, containing only one species each, form a 

 far greater constituent of British vegetation than do 

 Ophrys, Orobanche, Pyrola, and Scirpus, each containing 

 several. 



To depict the vegetation of a country, it hence becomes 

 necessary to state the comparative frequency and copious- 

 ness of each species. For a small space, this is readily 

 enough determined ; but local scarcity or abundance, 

 from differences of climate, soil, humidity, and other con- 

 ditions, so very materially interferes with any attempt to 

 do this for large tracts, that if two botanists, resident in 

 different counties, were requested to place the names of 

 a hundred species in a scale or series representing the 

 comparative degree of rarity or abundance, they would 

 be very unlikely to agree in their order of position. It 

 would, indeed, be sufficiently easy to select a hundred 

 species, which all British botanists would agree to call 

 rare ; and possibly a like number might be found, which 

 they would all of them esteem common ; but what could 

 they say about the other twelve or thirteen hundreds ? 



As an approximation to some estimate of the com- 

 parative frequency of occurrence of the different species, 

 in the table appended to this volume I have shown the 

 latitudinal and regional range of each species, and also 

 the number of published local Floras, and of my MS. Cata- 



