TEMPERATE ELOEAS 35 



agrees, however, very closely with the AVestern Himalayas as 

 estimated by Sir J. D. Hooker. 



Coming to the southern hemisphere, we find several ex- 

 amples of exceedingly rich floras. The first to be noticed is 

 Chile, where, in an area of 250,000 square miles, 5200 species 

 of flowering plants have been found. In Australia, Xew South 

 Wales, with an approximately equal area, has 3105 species, 

 while West Australia has 3242 species in what is probably 

 not more than one-fourth the area, as so much of that Colony 

 is absolute desert. 



But richer than either of these is extra-tropical South 

 Africa, where, in about a million square miles, 13,000 species 

 are known, and there are still probably many to be added. 

 The richest portion of this area is the Cape Eegion, as de- 

 fined by Mr. H. Bolus, where, in 30,000 square miles, there 

 are about 4500 species of flowering plants. This area is the 

 same as that of southern Britain, and about one-third that of 

 West Australia excluding the tropical portions and the desert. 



All these rich areas in the southern hemisphere agree in 

 one respect, they are limited inland hj mountains or deserts, 

 and their coast-line is bordered by a considerable extent of 

 sea less than 1000 fathoms deep, and another still larger 

 extent under 2000 fathoms. There is thus a high prob- 

 ability that in all these cases the flora was originally 

 developed in a much larger and more varied area, and that 

 it has been, in comparatively recent times, very greatly re- 

 duced in extent, thus crowding the various species together. 

 This has, no doubt, caused the extinction of some, while 

 others show that they are on the road to extinction by their 

 limitation to very narrow areas, as is especially the case with 

 many of the orchids, the heaths, and other characteristic 

 South African groups. Of course the mere submergence of 

 a large amount of lowlands would not, of itself, enable any 

 of its plants to invade the adjacent undisturbed land; but 

 the subsidence would no doubt have been very slow, and 



