118 ERYTHEA, 
the geography of plants. The region whose higher vegeta- 
tion is herein catalogued and scientifically discussed is a very 
natural one, and rather new to careful exploration; and the 
rather young state of Minnesota, by authorizing this sort of 
an undertaking, and bringing the whole to so noble an issue, 
has placed herself in the front rank of states in enterprise of 
natural history exploration and publication. 
The amount of botanical work which this book represents 
is vast indeed; and the quality of it, in general, excellent. In 
30 introductory pages are given the natural features of the 
country under investigation; a list of publications bearing on 
the botany of the region; a discussion of the subject of 
nomenclature; and an argument for that sequence of orders 
and genera which is adopted in the Catalogue. The Cata- 
logue itself, occupies 540 pages, and is followed by more 
than 200 pages devoted to various matters, geographical and 
statistical, bearing on this flora. 
For a year or two past, Professor MacMillan has been making 
his influence felt as a zealous and able exponent of principle 
versus usage in respect to botanical nomenclature, and in the 
work before us he has given the fullest expression to his 
views. Pages 11 and 12 of his Introduction contain state- 
ments of the difficulties of the present situation and their 
causes, and in terms that are both fresh and clear, though 
not always quite accurate; for it is not accurate to speak of 
priority as an “international law,” nor to say that, as such, it 
has “arisen,” as if recently. The fundamentality of the 
principle of priority has been recognized always and every- 
where in botany; only individuals, and especially since 
Linnzus, who set the example, have here and there made 
exceptions, more or less numerous, in favor of later and 
improved, or at least more widely published names. Priority 
was the ruling principle, not only before international oF 
even national congresses were, but almost before botany in 
any nation had risen to the dignity of a science. 
Very much of the recent controversy about nomenclature 
relates to the starting point from which priority ought to be 
dune Fo 
