1899] THE FLORA OF THE ALPS 113 



highest authority, gives the number as 2010, divided into 523 genera, 

 included in 96 natural orders. This is considerably richer than the 

 flora of our islands, notwithstanding our extensive sea-board and great 

 variety of soil and climate. A very few usually maritime plants are, 

 however, found in Switzerland, as the thrift (Armcria vulgaris var. 

 alpina) on lofty mountains, and the yellow horned poppy (Glaucium 

 luteum) on the shores of Lake Neuchatel. Of these species 1117, 

 arranged in 279 genera and 60 natural orders, belong to the upper 

 zone of the Alps. The largest number of species occur in the orders 

 Compositae, Leguminosae, and Gramineae, followed by the Cruciferae, 

 Cyperaceae, and Caryophylleae, each numbering over 100 species. 

 Both in the alpine flora in general and in that of the higher zone, the 

 number of Compositae is nearly double that of any other order, 

 numbering about one-eighth of the whole. Of the Saxifragaceae there 

 are 42 species, of the Primulaceae 36, of the Gentianaceae 26. 



The origin of the flora of the Alps is an interesting and somewhat 

 complicated problem. I have already pointed out the great difference 

 between the climatic conditions of Switzerland and those of the Arctic 

 zone. In accordance with what might be expected from this fact, a 

 close examination of the Swiss flora led the two highest authorities on 

 the subject, the late M. Alphonse de Candolle and the late Mr. John 

 Ball, to the conclusion that its nearest connection is not with the arctic 

 flora, but with that of the mountains of Central Asia, especially with 

 the Altai range. The arguments in favour of this view are very clearly 

 brought out by Sir W. T. Thiselton Dyer, in his introductory note to a 

 posthumous paper by Mr. Ball on the distribution of plants on the 

 south side of the Alps, read before the Linnean Society on the 2nd of 

 May 1895, and published in its Transactions (2nd ser. vol. v.). 

 According to Mr. Ball, while only 17 per cent of the species found in 

 the Alps are common to the arctic flora, 25 per cent are found also 

 on the Altai range. Still more convincing is the interesting fact that 

 some of the most remarkable and peculiarly alpine members of the 

 Swiss flora (genera or species) are found only on the south side of the 

 Alps, and are distributed at wide intervals throughout a discontinuous 

 mountain chain extending from the Pyrenees to Central Asia ; while 

 they are entirely absent from Central and Northern Switzerland, and 

 from the North of Europe. This is the case with species of 

 Oxytropis, Primula, and Pedicularis, and especially with Campanula 

 cenisia and its allies, and with the genus Wulfenia. 



I have touched on only the more conspicuous features of the 

 flora of the Alps. Those who have not yet turned their attention in 

 this direction will find how much is added to their enjoyment of an 

 alpine tour by even a slight acquaintance with its salient features. 



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