The Flora of Stewart Island (New Zealand) : a Study 
in Taxonomic Distribution. 
BY 
J. C. WILLIS, M.A., Sc.D., 
European Correspondent , Botanic Gardens , Rio de Janeiro. 
With two Maps and fourteen Tables in the Text. 
I N this paper I shall put together a few notes upon the flora of Stewart 
Island, the southernmost of the main chain of the New Zealand islands 
proper. I have carried on this study by the aid of my hypothesis of age 
and area, which indicates many new directions in which to search for facts 
that have hitherto passed unnoticed. My former predictions as to composi- 
tion and distribution made by its aid have been so successful, that in this 
paper I have adopted entirely the method of prediction and subsequent 
verification, giving fourteen different predictions about the plants of Stewart 
Island. The composition of the flora is first dealt with, and its geographical 
and other relationships. The subject of the probable invasions of New 
Zealand by plants, commenced in my last paper, is then followed up, in so 
far as the relationship of Stewart Island to these invasions is concerned, and 
it will be continued in papers on the floras of the more outlying islands. 
In publishing this series of papers on the geographical distribution of 
the New Zealand flora I am sometimes accused by botanists in Europe of 
trespassing upon a line of work which various New Zealand botanists have 
made peculiarly their own. These investigators have a real knowledge of 
the local conditions, whereas I possess none, and are turning out work 
of great value and importance, upon which I should not dream of trespass- 
ing. But I may be permitted to point out that their work is concerned 
with ecological, not with taxonomic, distribution, and it is to the latter that 
age and area refers. The two lines of work are really very distinct, and 
have comparatively little overlap. What is beginning to come out with 
great clearness from the study of age and area is that, given fairly uniform 
conditions, such as one finds in New Zealand, the distribution of the flora 
about the country, so far as the area occupied by the different species is 
concerned, is governed almost entirely by the law of age and area. The 
[Annals of Botany, Vol. XXXIII. No. CXXIX. January, 1919 
