5 86 
Sinnott and Bailey. — The Origin and 
It therefore seems probable, if our thesis is correct, that these endemic 
genera of herbs have arisen locally and quite independently in adaptation 
to the progressive refrigeration which has been taking place in the southern 
hemisphere as well as in the northern. That the climate of New Zealand 
has actually become much cooler in recent times is clearly shown by a study 
of the Tertiary fossils of the South Island. These include many sub-tropical 
plants, such as Agatkis, which are now restricted entirely to the northern 
portion of the Dominion. The Antarctic origin of herbs will be discussed 
more fully later. 
The flora of New Zealand presents many interesting affinities with that 
of Australia and the oceanic islands, regions which we have regarded as 
retaining a very ancient flora. The intimate relationship to Australia is 
especially well marked, for a large number of* genera (those which we have 
called 4 nearly endemic ’) occur in both regions and, with few exceptions, 
nowhere else. Such genera are Hymenanthera , Plagianthns , Olearia , 
Scaevola , Cyatkodes, Lencopogon , Persoonia , and others. There are also 
some remarkable affinities between the flora of New Zealand and those of 
the Pacific oceanic islands. The genus Gunner a is found in New Zealand, 
Tasmania, Hawaii, Juan Fernandez, South America, and South Africa; 
Metrosideros in New Zealand, Australia, and the Pacific islands ; Sophora 
tetraptera in New Zealand, Easter Island, Juan Fernandez, and Chile ; 
Cyathodes in New Zealand, Australia, Hawaii, and other Pacific islands ; 
and Coprosma in New Zealand, Malaysia, Hawaii, Juan Fernandez, and 
other islands. 
C. Patagonia and Fuegia. 
Patagonia and Fuegia are not isolated from a large continental area, as 
are the other regions which we have discussed, and in recent times, at least, 
they have been very freely open to immigration from the north. It seems 
probable, however, from geological evidence, that the free entrance of 
northern animals and plants into South America did not take place till the 
early Pliocene. Many ancient types are therefore preserved in the continent. 
We have already seen that herbaceous plants form less than 27 per cent, 
of the dicotyledonous flora of Brazil, and only 12 per cent, of the flora 
of the rain forests in the Amazon valley, a proportion which is much lower 
than that of any other continental area within the tropics. No analysis 
of the endemic genera is at hand, but practically all the characteristically 
Brazilian types are woody. It seems reasonable to infer that the ancient 
flora of tropical South America was almost entirely devoid of herbaceous 
plants. 
A somewhat more complete study was made of the flora of that part 
of temperate South America included in Patagonia and Fuegia. The 
following table presents an analysis of the dicotyledonous vegetation of this 
