THE SOUTH TEMPERATE ZONE 367 



grow a good many plants closely related to the bogs of the far 

 north, such as sundews, butter-wort (Pinguecula), marsh-marigold 



(Caltha), crowberry (Empetrum), and others. Of the lower ever- 

 green growths are various ferns, including a Uleichenia. Dac- 

 rydium and Orobolus are also characteristic genera. 



The Chilean flora, as might be expected from the great range of 

 latitude, shows marked differences between the north and south. 

 The extreme desert conditions of the north constitute an absolute 

 barrier against invasion of plants from the moist tropics. This 

 accounts for the complete absence in Chile of such striking families 

 as the Araceae, Scitamineae, Bignoniaceae, Malpighiaceae, and 

 the bamboos. The palms, so extensively developed in tropical 

 America, are restricted to two species, one of which, Juania 

 Australis, is confined to the island of Juan Fernandez. The 

 Bromeliaceae, more xero phytic in habit, have a considerable 

 number of representatives but are much less important than is 

 the case in most other parts of South America. 



On the other hand, owing to the cool and moist coastal climate 

 of central Chile, many sub-antarctic species extend far northward, 

 a condition parallelled in California by the southward extension 

 of many boreal species in the coastal redwood belt. In both regions 

 there is also a migration southward along the higher parts of the 

 great Cordillera. 



A comparison of the floras of California and Chile show upwards 

 of 150 genera in common, and although a large part of these arc 

 wide-spread in temperate climates, there are a good many strict ly 

 American genera, and some confined to the Pacific slope. Such. 

 for example, are many Cacti, the creosote-bush (Larrea), Bac- 

 charis, Encelia, Grindelia, Orthocarpus, Mirabilis, and others. 



There has been probably a migration in both directions, as some 

 genera are more characteristic of the north, others better developed 

 in the southern hemisphere. Thus Calandrinia, which has sonic 

 half dozen species in California, has many more in Chile, and also 

 Australia, and is presumably of southern origin. On the other 

 hand, Orthocarpus (Scrophulariaceae), with about 30 species in 

 Pacific North America, is represented by a single species in the 



Andes. 



While the number of species common to Chile and the Pacific 

 Coast of North America is small, there are several which could be 



