TEMPERATE FLORAS 



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Red Valerian, the Balm, the Martagon Lily, and many others. 

 This explanation is necessary in order to avoid any supposition 

 of positive error when the figures here given do not agree 

 with those of anv of the text-books or local floras. 



xJ 



The chief diiferences arise, however, from the increased 

 study of certain difficult groups leading to the separation of 

 large numbers of slightly differing forms, that hardly any 

 one but an expert can distinguish, as distinct species. The 

 most important of these are the Brambles (the genus Rubus) 

 and the Ilawkweeds (the genus Hieracium). During the last 

 thirty years the numbers of these have more than doubled, 

 according to the standard authority for British botanists — 

 The London Catalogue of British Plants. The numbers in 

 an early and late edition are as follows : — 



In the last two cases two well-known plants — the little 

 " eyebright " of our turfy banks, and the '' yellow rattle " of 

 peaty meadows, which have been each considered to form a 

 single species from the time of Linnseus to that of Bentham 

 and Hooker — are now subdivided into a number of distinct 

 species, each claimed to be well recognisable and constant. 

 With such rapid changes in the estimate of species in so 

 well-known a flora as our own it may be thought that the 

 number of species in foreign countries is even more uncertain. 

 This, however, is by no means the case, as tlio great 

 majority of the species of plants a^ well as of animals; offer 

 little difficulty, and present few fixed varieties (though 

 abundance of variation), so that for general comparisons the 



D. H. HILL LIBRARY 



