IV. ^^3GETATI0N OF BRITAIN. 415 



view, there may he said to remain still something of the 

 numerical character, in comparing one tree with many 

 herbs. But when mere size is under consideration, even 

 that rude approach towards numerical comparabilit}' 

 seems to fail and become no longer available. 



How many plants of Centunculus are equivalent to one 

 of Digitalis ? — How many tufts of Juncus effusus are 

 equivalent to one tree of Taxus baccata ? — Answer these 

 queries to yourself, sensible reader, as best you can ; and 

 then recollect that like queries and answers should be 

 extended also to each one of the whole 1425 sj)ecies, com- 

 pared with each and all of the rest. It seems almost 

 hopeless to expect any sort of answer, such as can be 

 brought to bear correctly upon ordinal proportions. We 

 may compare together the numbers of species included in 

 different orders. We may also less precisely compare 

 the number of their repetitions, or the extent of their 

 areas, with the object of ascertaining comparative fre- 

 quency. But the further effect and influence of their 

 relative size, in constituting the mass of vegetation, can 

 scarcely be noted otherwise than empirically, as a sort of 

 physiognomical character ; one often obvious to the eye, 

 but not admitting of measurement or computation. 



How best to present the joint result of numbers and 

 frequency, leaving size and compound character out of 

 the question ? — It is undeniable that the census of 

 species before printed, pages 234 to 271, and the third 

 column of figures in the census of orders, pages 359 to 

 301, must present a better summary of the vegetation, 

 than any other census can do, which is restricted to the 

 number of species, exclusively of their frequency. It is 

 then to that tliird column, as an ordinal summary of the 

 census of species, we must look for an answer to the 

 question. The figures in that column represent the 



