THE oe(1(;rapiiical nisTniiu'Tiox of plants. 115 



In tbe southern hemisphere, "we find a very different state of 

 things. There the great continents, separate from each other from 

 a most remote period, possess floras strikingly distinct from each 

 other, so that it is necessary to assign to each great body of land 

 its own distinct Flora. This gives us 



The Australian Flora, showing some slight traces of connection 

 with the region to the north of it and with New Zealand. Aus- 

 tralia has been so long separated from the other bodies of laud, 

 that its flora has had time for a great deviation from that of other 

 countries. Indeed it is notorious for its uulikeuess to that of any 

 other country. 



Next the Andean Flora, that of South America, which shows 

 some very slight connection with that of New Zealand and 

 Australia. 



Then the Mexico^Califoryiian, which extends up the west coast 

 of America from Chili to Mexico and even iuto California, being 

 the source of many of our present Calif ornian species. 



Lastly the South African is very rich in species and remarkably 

 varied. And just as our North Temperate plants have representa- 

 tives far south of them on the mountains, so these Southern Floras 

 have some of their members on mountains away to the North. ' ' The 

 plants of Fuegia extend northward along the Andes, ascending as 

 they advance. Australian genera reappear in Borneo and even 

 cross to China and Japan. New Zealand forms are on the 

 mountains of New Caledonia ; South African in the Lake Region of 

 Africa, in North Africa, and even to the Canaries and Asia Minor." 

 And in all these cases, the southern, like the northern, forms ascend 

 the mountains as they approach the equator, and descend toward 

 the sea level after they have crossed it. 



Now what is the history of these widely separated regions? 

 There seems every probability that in times far back all these 

 floras came, not from the south but from the north ; and the 

 time when they had a common home there is so remote that the 

 floras have had time to diverge greatly. That this is the correct 

 view is sustained by the fact that these southern floras are much 

 more like those immediately to the north of them than they are 

 like one another ; that there is no evidence of a southern continent 

 from which they could have come ; that while most peculiar 

 species of the South have relatives either living or fossil in the 

 North none of the northern forms have fossil relations in the 

 South. 



