230 NATURAL SCIENCE. October. 



to endeavour to account for them." Selecting the southern side of 

 the main chain of the Alps as having the richest and most varied 

 flora, he divided it into fifty districts, and set himself to collect 

 materials from published works and herbaria, but chiefly from his 

 own repeated visits. For nearly thirty years he worked at the collec- 

 tion and tabulation of the plants of these fifty districts, and their 

 distribution on other European mountains. Unfortunately, at his 

 death, in 1889, the work was still incomplete, and for his conclusions 

 from all this mass of material, we are entirely dependent on his 

 lecture at the Geographical Society of ten years before. Mr. Thistleton 

 Dyer undertook the editing of the table, which occupies one hundred 

 pages of the Linnean Society's Transactions, and will be a valuable 

 basis for further work. Without doubt, facts of the highest interest 

 lie buried in its columns, but it will need a skilled botanist, and one 

 who has studied Alpine floras well, to bring them to light. If the 

 entries are treated as mere symbols, misleading or false conclusions 

 will arise. In working in this way with all the plants of a flora, 

 critical and doubtful species will, unless great care be taken, exercise 

 an important influence on statistical results. A safer and simpler 

 method of studying the relations of the local floras of large areas is 

 the one recommended by Mr. C. B. Clarke in an address to the 

 Linnean Society, to which we referred in Natural Science (vol. viii., 

 p. 366, June, 1896). It is the selection of a limited number of common 

 and unmistakeable plants, and a careful elaboration of their distribu- 

 tion and habitat. 



According to Mr. Ball the Alps, as a whole, contain 2,010 species 

 of flowering plants, representing 523 genera and 96 natural orders. 

 Compared with the floras of other regions, a large proportion of 

 the species, more than two-fifths, are found in all parts of tem- 

 perate Europe, the majority extending to Siberia, and many even 

 to North America. " These are clearly plants that have a consider- 

 able power of adapting themselves to varied physical conditions, and 

 whose vigorous organisation has made them victorious in the struggle 

 for existence." Of these, however, not one in twelve (actually only 

 65 in 792) can be reckoned as plants of the higher mountain region ; 

 most of them are common enough in the lower zone, but grow equally 

 well in the woods and heaths and waste grounds of Middle Europe. 

 Subtracting also some Mediterranean stragglers, we have a special 

 Alpine flora of about 1,150 species. Of these "more than one-seventh 

 are endemic, rather more than half are common to the Alps and the 

 Pyrenees, just two-thirds are common to the Alps and Carpathians, 

 while rather more than one-sixth are common to the Alps and the 

 north of Europe and Asia." Compared with other mountain regions 

 not immediately adjoining, the closest affinity is found to be with the 

 mountains of Northern Asia, notwithstanding the vast interval of 

 space and the great difference in cHmate. Of every twelve Alpine 

 species, three are to be found in the Altai, but only two in the Caucasus, 



