STATISTICS OF METASPERMAE. 653 
younger element, may be expected to mass themselves more dis- 
tinctly in lines parallel with the general continental tension-line. 
The Monocotyledones, being peculiarly the older and more gen- 
erally distributed element, may be expected to manifest dissipa- 
tion over the different degrees of latitude. This they are found 
to manifest, so the relative development of the two groups is 
admirably exhibited by these data of comparative latitudinal 
and longitudinal distribution. 
The total per cents. are of importance, too, as determining in 
a preliminary way the character of the Minnesota valley 
flora, so far as regards its North American distribution. We 
find that the relations are as follows: 
Total Northern..... 163 Northern per cent. of all genera....39.9 
Total Southern......254 Southern per cent. of all genera....62.2 
Total Eastern....... 270 Eastern per cent. of all genera...... 66.1 
Total Western...... 183 Western per cent. of all genera..... 44.8 
So far then as may be indicated by the genera of metaspermic 
plants, the valley of the Minnesota is much more eastern and 
southern in its character than northern or western. Although 
generally regarded as a northern district, it is seen to be least 
characterised by this range-element. While continentally cen- 
tral it is by no means botanically central, but is peculiarly an 
Atlantic coast and a southern region. The explanation of this 
may be deferred until the examination of the species-distribu- 
tion has been completed. 
III. EXAMINATION OF SPECIES REPRESENTED IN THE 
MINNESOTA VALLEY. 
Since 73.0 per cent. of the species in the Minnesota valley 
native metaspermic flora are limited to the North American 
continent it will hardly be worth while to attempt any ex- 
tended examination of them along the lines of Table A or 
Table B. The extra-continental element may be isolated for 
study and the remainder which will consist of the endemic 
species may be classified as were the genera in Table C. The 
area occupied by a species is, as De Candolle has shown, in 
general either circular or elliptical. The species which are 
found in the Minnesota metaspermic flora are without excep- 
tion to be found also outside of the basin. Each species or 
variety occupies such an elliptical or circular area as may be 
