340 
Willis. — Further Evidence for Age and Area; 
Leaving age and area entirely out of the consideration, it is generally 
accepted that the Ferns are on the whole a much older group than the 
Angiosperms. One may therefore obtain a good crucial test as to whether 
it is age or youth that goes with area occupied. If the endemics be older 
species dying out, then it is evident that fern endemics should occupy less 
area than angiosperm endemics ; but if, on the other hand, my hypothesis 
be accepted, then they should occupy more. The actual facts give us for 
the Ferns : 
Table III. 
Wides (including those only reaching the outlying islands) 
Endemic to New Zealand proper 
Number. 
104 
24 
Rarity 
(Figs. i-]Q). 
3-2 
3-8 
The corresponding figures for Angiosperms ( 9 , p.449) were 3-5 and 6-5. 
The Ferns therefore, whether wide or endemic, show a wider distribution in 
New Zealand than the Angiosperms. This is especially the case with the 
endemic Ferns, which range on an average 734 miles, against a range of 
400 for an angiosperm endemic. 1 This agrees with what is required under 
my hypothesis, but is very difficult to harmonize with the idea that 
endemics are old species dying out. 
Why, whilst the endemics show this great difference in favour of the 
Ferns, the wides should only show an increased range of thirty-six miles is 
not altogether clear. The explanation which I would suggest is that as we 
know that fern spores may be carried to great distances by the wind, and 
as we have actual examples in which Ferns have arrived in new places over 
considerable distances with no intermediate halting-places, e. g. the summit 
of Ritigala in Ceylon ( 12 ), or the sterilized island of Krakatoa near 
Java (6, 8), land connexion is not so necessary as it is in the case of Angio- 
sperms. There is no reason why new Ferns should not occasionally arrive 
in New Zealand subsequently to . the breaking of the land bridge, though 
the figures already given rather go to show that most of them arrived by 
that way. If we accept this hypothesis, which is not very far-fetched, there 
is no difficulty in understanding why there are so many wides with but 
a small range in New Zealand, though they may be widely dispersed 
abroad. It does not affect the question of the endemics, because one of 
these which became established beyond the sea would cease to be an 
endemic. Nor does this behaviour of the wides give any encouragement to 
the supporter of Natural Selection, or of the idea of dying out of old 
species. 
We may get a clearer insight into this question by splitting the Ferns 
of New Zealand into four groups, according as to whether they do or do 
1 Each unit of rarity represents 120 miles of range; 6*5 means 400 miles, 5*5 means 520, and 
so on. 
1 
