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 (Armeria vulgaris var. 
alpina) on lofty mountains, and the yellow horned poppy (Glauciwm 
lutewm) 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. 
6 PARK VILLAGE East, 
REGEN'’s Park, N.W. 
8—wNaT. sc.—voL. xv. No. 90. 
