734 METASPERMAE OF THE MINNESOTA VALLEY. 
east and west distribution of the Monocotyledones of the extra- 
continental element indicated by the figures 93.9 and 76.7 is 
moreeven than that of the Archichlamydeae of that element, 
indicated by the figures 93.0 and 70.7. On the other hand the 
north and south distribution of the Archichlamydeae of the ex- 
tra-continental element is more even than that of the Monoco- 
tyledones, as indicated respectively, by the relations between 
the figures 83.1—50.0 and 86.2—47.4. But in comparison with 
the general specific elements we see, as for the Monocotyle- 
dones, an increase in average northernness, a decrease in aver 
age longitudinal equality of distribution and an increase of 
lateral equality. 
Of the total specific elements the Metachlamydeae run 41.6 
per cent. northern, 83.9 per cent. southern, 82.9 per cent- 
eastern, 51.9 per cent. western. Of the extra-continental ele- 
ment they run 76.1 per cent. northern, 57.7 per cent. southern, 
92.9 per cent. eastern and 80.2 per cent. western. Of the three 
taxonomic groups, then, the Metachlamydeae show the 
greatest evenness of longitudinal distribution. In other words, 
this group is least concerned in the northern-region influence. 
Further the Metachlamydeae are most evenly distributed east 
and west, of the extra-continental groups. As before, however, 
but with diminished ratios, the Metachlamydeae, in comparison 
with the Metachlamydeae of the total specific elements, show 
an increase in average northernness, a decrease in average 
longitudinal equality of distribution, an increase in average 
lateral equality of distribution. These three indices of extra- 
continental ranging in its relation to intra continental distribu- 
tion reduce themselves to this: The extra-continental element 
is more widely distributed intra-continentally than the general 
intra-continental element. It is. more evenly distributed 
laterally and less evenly distributed longitudinally. The three 
taxonomic groups are in any case of different value in relative 
cosmopolitan or endemic distribution. These differences per- 
sist and are accentuated in the extra-continental element. Since 
the endemic character is at once preponderantly metachlamy- 
deous and also of the Central element, it happens that the lon- 
gitudinal distribution of extra-continental Metachlamydeae is 
more even than that of the other two groups, for the general 
southern and specific northern influences are best able in this 
group to neutralise each other. 
From the above condensed account of the extra continental 
specific element it will be seen that every figure, in comparison 
