New Zealand and their Distribution . 271 
Table IV. 
Reaching She of Families in Stewart Island. 1 
3 islands. 54, 38, 30, 21, 17, 14, 13, 13, 13, 10, 7, 7, || 4, 4, 3, 3, 3, 1, 1. 
2 „ 12, 10, 10, 8, || 6, 4, 4, 3, 3, 3, 2, 2, 2, 1. 
1 island. |) 4, 4, 4, 3, 3, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1. 
No islands. || 4, 3, 2, 1, r, 1, 1, 1, 1, 1, 1. 
A mere glance at these figures is enough to show that the prophecy 
is borne out by the facts ; but we may put it in tabular form thus : 
Table V. 
New Zealand Families. Stewart Families . l 
Reaching 
Fams. 
spp. 
Average size , 
Fams. 
spp. 
Average size. 
3 islands 
*9 
896 
47.1 
19 
256 
I3’4 
2 ,, 
20 
293 
14.6 
14 
70 
5 -° 
1 island 
20 
112 
5.6 
16 
34 
2.1 
No island 
32 
9 1 
2.8 
11 
l 7 
i-5 
(4) Just as we predicted in the case of Stewart that the New Zealand 
families omitted would be on the whole the smallest, so here we may 
predict that the missing Stewart families will on the whole be the smallest, 
a prophecy which is clearly borne out by the facts in Tables IV and V. 
(5) One will expect the Aucklands to contain many of the families 
of the southern invasion — they contain all but Naiadaceae. One will 
expect the Chathams also to contain many.’ and on the whole to lack the 
smaller ones. The smallest, those with less than 1 1 species, are Portula- 
caceae, Droseraceae, Stylidiaceae, Plantaginaceae, and Centrolepidaceae, 
and it is exactly these which are missing in the Chathams. The bulk of 
the invasion, if not all of it, is missing in the Kermadecs. 
(6) One will expect the Chathams to contain many of the families of 
the northern invasion, and perhaps the Kermadecs also, but, as we have 
already seen (10, p. 358), they do not seem to have lain in the track of 
the main invasion. Examination of the facts shows that the Chathams 
contain only 9 of the 33 families, and the Kermadecs 11, while Stewart 
itself only contains 8 and the Aucklands 3. It is thus evident that old 
though it was, the northern invasion did not in general get very far south. 
This may have been due to the species reaching their climatic boundary, 
in some cases at any rate, though my experience of the surprising degree 
of cold which many ‘ tropical * species bear in southern Brazil, and the fact 
that so many tropical species go very far south in New Zealand, makes 
me hesitate to say that a species has reached its climatic limit. Given 
slow enough progress, a species may travel into climates to which it would 
seem quite unsuitable. 
1 Note the much greater proportion of the Stewart families reaching islands, even three islands. 
The Stewart families are on the whole older. 
