364 Willis .— The Sources and Distribution of the 
age of woody vegetation, and that, as in that case, the investigation of any 
one or two floras is quite insufficient to provide a solution. 
If, as Dr. Sinnott suggests, the absence of wides in a genus had any¬ 
thing to do with the age of the genus, one would rather expect to see some 
difference in the figures of distribution of the two classes, especially in the 
zonal figures, in which Cook’s Strait may interfere with the younger forms. 
But in actual fact the figures for the two classes show the most extraor¬ 
dinary similarity: 
Table V. 
Southern genera. 
Swamped 83 
no 
139 
*5 8 
179 
236 
240 
242 
232 
186 
75 
Not 45 
64 
82 
99 
112 
18 S 
i93 
202 
189 
152 
48 
Northern genera. 
Swamped 77 
78 
76 
7 2 
58 
56 
50 
37 
32 
3i 
12 
Not 11 
11 
11 
7 
7 
7 
6 
6 
4 
3 
3 
The parallelism is most remarkable, and both groups show the holding 
up at Cook’s Strait almosCequally in the southern genera, and not at all 
in the northern. 
A very interesting comparison, which does not harmonize very well 
with the hypothesis of swamping, may be made among the various classes 
of wides. There are 66 genera containing both wides and endemics, 99 with 
wides only. Of the 66 , 35 genera have a second wide species, and 22 more 
than one, and of the 99, 24 genera have at least one extra species, and 
5 more than one. This alone would go to show that it was mainly the older 
wides which gave rise to the endemics. But now if we pick out first the 
commonest (most widespread) wide in each genus, next the second 
commonest (for the 35), and the others (for the 22), but, as the numbers are 
small, lump together all the others for the 24 genera with no endemics and 
more than one wide, we get: 
Table VI. 
Wides with endemics. Wides without endemics. 
Class. 
First. 
Second. 
Others. 
First. 
Others . 
1 
37 (56 %) 
13(37%) 
7 ( 10 %) 
21 ( 21 %) 
4 (12 %) 
2 
9 
5 
9 
27 
13 
3 
3 
3 
14 
9 
— 
4 
4 
4 * 
11 
8 
2 
5 
5 
1 
6 
8 
1 
6 
3 
3 
4 
9 
— 
7 
1 
— 
7 
7 
2 
8 
1 
5 
3 
5 
3 
9 
— 
— 
3 
5 
2 
10 
3 
5 
— 
5 
66 
35 
69 
99 
S 2 
Rarity 
2*5 
3*4 
4-5 
3-6 
4*6 
It will be seen at a glance that the commonest wides in the genera 
with endemics are much more widespread than those in the genera without, 
