STATISTICS OF META SPERM AE. 733 



The third table of the series showing the North Ameri- 

 can range of extra-continental Minnesota valley metas- 

 permic species and varieties presents some interesting per- 

 centages. Of the total element 85.9 per cent are northern and 

 50. 7 per cent southern in North America. Comparing with 

 the general tables of the entire flora, we find that 55.6 per cent 

 of the species are northern while 76.1 per cent are southern. 

 This indicates the predominent northern character of the extra 

 continental specific element. Its presence in the Min- 

 nesota valley is therefore principally to be referred 

 to the influence of the Conifer region of Engler or the 

 Northern of Drude, which lies just above the latitude of the 

 Minnesota valley. Of the extra-continental element 93.3 per 

 cent, is eastern and 75.4 per cent, western. Comparing again 

 the tables for the entire metaspermic flora we find that 87.2 per 

 cent, are eastern and 51.4 per cent, western. The diiference be- 

 tween the general percentages is therefore greater than be- 

 tween the extra-continental percentages. This indicates a 

 more general latitudinal distribution of extra-continentally 

 ranging species than of the average species of the valley. 

 Since, however, this extra-continental element is so preponder- 

 antly northern the longitudinal distribution is not equal to the 

 average longitudinal distribution. The extra-continental ele- 

 ment is therefore distinctively lateral rather than vertical in 

 its charactistic inter-continental distribution. 



Besides the comparison of totals, the comparative distribu- 

 tion of the three taxonomic groups will be worth a moment's 

 attention. Of the total specific elements the Monocotyledones 

 run 68.2 per cent.northern,69.1 per cent, southern, 93.6 per cent, 

 eastern, 53.1 per cent, western. Of the extra- continental ele- 

 ment the Monocotyledones run 86.2 per cent, northern, 47.4 

 percent, southern, 93. 9 per cent, eastern, 76.7 per cent, western. 

 These figures indicate for the extra-continental Monocoty- 

 ledones an increase in average northernness and a decrease in 

 average longitudinal equality of distribution, together with an 

 increase of lateral equality of distribution. 



Of the total specific elements the Archichlamydeae run 55.9 

 percent, northern, 75.1 per cent, southern, 86.1 per cent, east- 

 ern, 49.6 per cent, western. Of the extra-continental specific 

 element the Archichlamydeae run 83.1 per cent, northern, 50.0 

 per cent, southern, 93.0 per cent, eastern, 70.7 per cent, west- 

 ern. These figures preserve an exact parallelism with those of 

 the Monocotyledones, but with varying internal ratios. The 



