DR. HOOKER ON THE DISTRIBUTION OF ARCTIC PLANTS. 259 
Scandinavian forms ; for these belong to the remotest corner of the Scandinavian a rea 
and should of all plants be the most impatient of temperate, warm, and tropical climates. 
The following will, approximately, express the result 
Total Arctic Scandinavian forms . . . .586 Cross Alps, &c 480 
In North United States and Canada, &c. . 360 Reach South Africa 20 
In Tropical America 40 Himalaya, &c 300 
In Temperate South America 70 Tropical Asia 20 
In Alps of Middle Europe, Pyrenees, &c. .490 Australia, &c .60 
In one respect this migration is most direct in the American meridian, where more 
arctic species reach the highest southern latitudes. This I have accounted for (Flora 
Antarctica, p. 230) by the continuous chain of the Ancles having favoured their southern 
dispersion. 
But the greatest number of arctic plants are located in Central Europe, no fewer than 
530 out of 762 inhabiting the Alps and Central and Southern Europe, of which 480 cross 
the Alps to the Mediterranean basin. Here, however, their further spread is apparently 
suddenly arrested ; for though many doubtless are to be found in the Alps of Abyssinia 
and the western Atlas, these are few compared with what are found further east in 
Asia ; and fewer still have found their way to South Africa. 
The most continuous extension of Scandinavian forms is in the direction of the greatest 
continental extension ; namely, that from the North Cape in Lapland to Tasmania* ; for 
no less than 350 Scandinavian plants have been found in the Himalaya, and 53 in 
Australia and New Zealand ; whereas there are scarcely any Himalayan and no Austra- 
lian or Antarctic forms in Arctic Europe. Now that Mr. Darwin's hypotheses are so far 
accepted by many botanists, in that these concede many species of each genus to have had 
in most cases a common origin, it may be well to tabulate the generic distribution of 
arctic plants as I have done the specific ; and this places the prevalence of the Scandina- 
vian types of vegetation in a much stronger light ; 
m 
Scandinavian Arctic Genera in Europe . . 280 Cross Alps (approximately) .... 
Found in North United States (approximately) 270 Found in South Africa (approximately) 
</ 
» Tropical American Mountains „ • 100 „ Himalaya, &c. 
» Temperate South America „ ,120 „ Tropical Asia 
» 
Alps 
„ • , 280 » Australia, &c. 
;• 
v 
55 
260 
110 
270 
80 
100 
The most remarkable anomaly is the absence of Primula in Tropical America, that 
genus being found in Extra-tropical South America; and its absence in the whole 
southern temperate zone of the Old World, except the Alps of Java. 
The line which joins these points passes through Siberia, Eastern China, the Celebes Islands, and Australia, 
but the glacial migration has no doubt been due south from the arctic and north temperate regions in various 
longitudes to the Pyrenees, Alps, Carpathians, Caucasus, Asia Minor, Persian and North Indian mountains, &c. The 
farther migration south to the distant and scattered alpine heights of the tropics, and thence to South Australia, 
Tasmania, and New Zealand, is, in the present state of our knowledge, to me quite unaccounted for. Mr. Darwin 
assumes for this purpose a cooled condition of the globe that must have been fatal to all such purely tropical vegeta- 
tion as we are now familiar with. 
XXIII 
2 
