JOHN MACOUN ON CANADIAN POLYPETALZÆ, 155 
tions of Darwin as regards natural selection, but they are keeping within their own 
limits. 
4. Let us now turn to the past. In Sir Joseph Hooker’s “Arctic Manual of Instruc- 
tion, 1875,” at page 380 there is a list of the Miocene plants of the Arctic Regions, by Heer, 
numbering 353 species: of these 88 are Polypetalæ, and only seventeen belong to the 
orders which are so extensive now. The six most prominent orders of the Miocene 
Polypetalæ are :— 




oe eee | | = —— 
NaomOACEæ Agoda oaaduacgds 6on0 ooLc 1 4 11 | 
Menispermaceæ .....,.......,.,..... 1 5 3 | 
STi TEL Cope eee ete eee seen core 1 6 | 4 | 
RRADINACER eme essences 7 | 6 | 10 
Ébiotubieradeocmaccocenorononaenoo 10 | 6 | 17 
OHRNACO RE eee COCO seat 12 | 15 | 10 
= Des | | 
Ioinloncené poootoecoranet'occece 32 42 55 




Including the twelve orders mentioned, we have forty-nine species out of a total of 
eighty-eight, and the genera to which they belong are chiefly represented in our flora. It 
would seem, therefore, that the small orders are the remnants of vegetation of the past, and 
that, if there be any links to connect the Magnoliaceæ and the Ranunculaceæ (the Dilleniaceæ 
are wholly southern) or the Sapindaceæ with the Leguminose, we must look to the Pliocene 
for such connections. The imperfection of the record is certainly a good excuse, but there 
is a great gap between the Crowfoots and the Magnolias, and, when I look to the tulip-tree 
which is evidently the older, towering to the heavens and adorned with its clusters of 
lovely flowers, and to the lowly buttercup at its foot, lam led to ask ifthis can be a product 
of natural selection and if plants like men are under a curse. 
5. I have stated that I believe our large orders are the newer types and the small ones 
the older creations. My reasons for these statements are that this variation is apparently 
still going on in these orders, and many of the species and even genera are difficult to limit. 
They are chiefly confined to the temperate regions and have few representatives in the 
tropics. On the other hand the small orders were prominent in the Miocene, they have 
ceased to vary and are more largely represented in the localities where, if my opinions are 
correct, both the north temperate and south temperate floras retreat when they are dis- 
placed by the vigorous forms originating further to the north or to the south. By this 
simple law of displacement (for it is a law, which all enforced or voluntary emigrations 
prove), and the variations consequent on the change of habitat, new races are being consoli- 
dated into species, and, as change after change in the physical condition of the earth takes 
place, these either pass out of existence, or are forced to the south whence they never return. 
It is a simple matter to acclimatize a northern species at the south, but a serious business 
to change the constitution of a southern one so as to resist the cold. Hence I infer that a 
