Over a South Atlantic Continent 447 



that then prevailed, and of which we now have direct evi- 

 dence. 



Thus such genera as Podocarpus*, Ephedra, Libertia, 

 Chloraea, Acaena*, Discaria, Fuchsia'^, Oreomyrrhis, 

 Azorella"^, Empetrum*, Pernettya'^ , Buddleia, Colloniia, 

 Nama, Pectocarya, Plagiohotrys, Lycium, Jaborosa, 

 Nierembergia, Veronica^, Ourisia^ , Calceolaria, Cruck- 

 shanksia, Pratia*, Boopis, Vittadinia^ , Baccharis, Tessaria, 

 Chevreulia, Verhesina, Lagenophora, Tagetes, and Dy- 

 sodia, — to mention only a few amongst some sixty-five 

 other genera — are more or less continuous in distribution 

 from Peru, from Mexico, or even from western and 

 central N. America down to Patagonia, and may be in 

 some cases continued across to N. Zealand or Tasmania, 

 as is true of those with asterisks above. The highly evolved 

 and typically Mexican-S. American group of the Com- 

 positae-liguliflorae, in such genera as Chaptalia, Leuceria, 

 Mutisia, Nassaiivia, Perezia, Lasiorrhiza, and Proustia, all 

 extend from N. Chile or even from Mexico and the south- 

 ern United States to South Patagonia. 



But a study of the flora of the Juan Fernandez and of 

 the Galapagos Islands, reveals that all of these show quite 

 a number of plants which in genera or even species are 

 identical with or closely allied to those of the American 

 mainland. Thus in the valuable studies of Johow (275) 

 he has listed 236 species from Juan, 62 of which are 

 endemic to the islands, 64 are common to them and to 

 Chile-Peru, 24 were intentionally, and the remainder were 

 unintentionally introduced by man. The distribution of 

 some of these is noteworthy. Lobelia anceps is found in 

 Juan, Chile, S. Africa, New Zealand and Australia. Halo- 

 ragis alata is a small shrub common to Juan, New Zea- 

 land and South Australia, and which often grows in Juan 

 beside Pernettya rigida. The latter genus includes about 

 40 species, 15 of which are found from Mexico and Costa 

 Rica to Chile, 2 from Chile to Magellan, i is peculiar to 

 Juan, and i to Tasmania. But Pernettya and the nearly 

 allied ericaceous shrub Gaidtheria seem both to have 

 evolved and diverged from a common ancestry in Central 

 America or in northern S. America. Gaidtheria spread 



