chap, xxii.] THE FLORA OF NEW ZEALAND. 
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to the great western island, along with the peculiar Acacias and 
Eucalypti, which at a later period spread over the whole con- 
tinent. It is equally accordant with the view we are maintain- 
ing, that among the groups which Sir Joseph Hooker enumerates 
as “ keeping up the features of extra tropical Australia in its 
tropical quarter,” several should have reached New Zealand, 
such as Drosera, some Pittosporeae and Myoporineae, with a few 
Proteaceae, Loganiaceae, and Restiaceae ; for most of these are not 
only found in tropical Australia, but also in the Malayan and 
Pacific islands. 
Tropical character of the New Zealand Flora explained. — In 
this origin of the New Zealand fauna by a north-western route 
from North-eastern Australia, we find also an explanation of the 
remarkable number of tropical groups of plants found there : 
for though, as Sir Joseph Hooker has shown, a moist and uni- 
form climate favours the extension of tropical forms in the 
temperate zone, yet some means must he afforded them for 
reaching a temperate island. On carefully going through the 
Handbook, and comparing its indications with those of Bentham’s 
Flora Australiensis, I find that there are in New Zealand thirty- 
eight thoroughly tropical genera, thirty-three of which are found 
in Australia — mostly in the tropical portion of it, though a few 
are temperate, and these may have reached it through New 
Zealand . 1 To these we must add thirty -two more genera, which, 
1 The following are the tropical genera common to New Zealand and 
Australia: — 
1. Melicope. Queensland, Pacific Islands. 
2. Eugenia. Tropical Australia, Asia, and America. 
3. Passiflora. Queensland, Tropics of Old World and America. 
4. Myrsine. Tropical and Temperate Australia, Tropical and Sub-tropical 
regions. 
5. Sapota. Australia, Norfolk Islands, Tropics. 
6. Cyathodes. Australia and Pacific Islands. 
7. Parsonsia. Tropical Australia and Asia. 
8. Geniostoma. Queensland, Polynesia, Asia. 
9. Mitrasacme. Tropical and Temperate Australia, India. 
10. Ipomcea. Tropical Australia, Tropics. 
11. Mazus. Temperate Australia, India, China. 
12. Vitex. Tropical Australia, Tropical and Sub-tropical. 
13. Pisonia. Tropical Australia, Tropical and Sub-tropical. 
