JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



levels of the north temperate zone to the north, and up the high 

 mountains. At the present day a large number of the charac- 

 teristic plants of our British mountains, the Pyrenees, the Alps, 

 the Himalayas, and the Rocky Mountains of North America, 

 grow also in the Arctic zone. It is estimated that in Europe 

 alone there are not less than one thousand plants out of ten 

 thousand that belong to this group, the three specially repre- 

 sentative genera of which are Primula, Gentiana, and Saxifraga. 



Geographical Distribution. — The following table will give a 

 general idea of the distribution of Saxifrages. It is taken, with 

 trifling alteration, from the excellent monograph of the genus 

 which was published in 1862 by Professor Engler. He defines 

 166 species, and adding to this the Bergenias, which he excludes 

 from the genus, and the new species which have been discovered 

 in Central Asia, the number will be raised to 180. These are 

 distributed as follows : — 



Species 



Central European Alps 42 



Himalayas 35 



Pyrenees 30 



Carpathians 25 



Ptocky Mountains 22 



China 20 



Apennines 19 



Eastern Siberia 17 



Southern Spain 16 



Roumelia and Greece 14 



Scandinavia 1-4 



Caucasus 13 



France west of the Rhine 13 



Britain . 12 



Altai 11 



Jura . . . .9 



South American Andes 5 



Australia, New Zealand, and the Cape 0 



The species which are spread through the whole of the north 

 temperate zone are nine in number, and out of this seven are 

 British. The British cosmopolites are cernua, Hirculus, 

 stellaris, tridactylites, nivalis, oppositifolia, and caespitosa ; and 



