498 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



scopuJorum represent the zone of strife cither between the mon- 

 tane pine forests and the grassy plains, as for Instance in western 

 Nebraska and northern Colorado, or between the former and the 

 chaparral belt in southern Colorado. Sometimes the latter 

 disappears and the strife is between the Montane and the Upper 

 Sonoran. 



20. That the Chaparral Belt is the true representative in the 

 Rockies of the Alleghanian Zone or submontane hardwoods of 

 Europe. 



21. That the Great Plains north of the Arkansas Divide repre- 

 sent the grasslands of this zone and not of the Upper Austral or 

 Upper Sonoran, as partly claimed by Dr. Merriam. They begin 

 at about the same latitude as that at which the chaparral dis- 

 appears. That the higher part of the Columbia Plains also belongs 

 to this life zone. 



22. That the Staked Plains south of the Arkansas Divide should 

 be counted in the Upper Sonoran Zone as well as the Great Basin 

 and a part of the Columbia Plains. In this I agree with Dr. 

 Merriam. 



23. That Dr. Merriam is right in counting the Lower Sonoran 

 to the warm temperate zones and Marcus E. Jones wrong in 

 placing it among the tropical. 



24. That the prairie region of the Upper Austral Zone of the 

 East sends long arms along the valleys of Missouri, Platte, Ar- 

 kansas, and other rivers into the Great Plains, which arms carry 

 some of the prairie plants to the foot of the Rockies. 



25. That the Lower Sonoran sends up similar arms along the 

 Colorado of the West and its tributaries and the Rio Grande. 



26. That the mountain regions of the middle division may be 

 divided into three parts which show some differences in the 

 composition of the flora, viz., the Northern Rockies, the Southern 

 Rockies, and the Sierra ]\Iadre. The division lines in the Montane 

 Zone between these are the saddles in central Wyoming and New 

 Mexico, not near the Canadian and Mexican boundaries as Harsh- 

 berger has indicated. In the Submontane Zone the division line 

 on the eastern slope is further south about the headwaters of the 

 South Platte River, and the I'ppcr Sonoran on that side stops on 

 the Arkansas Dixidc. On the west side the latter cxlcnds north 

 to the Columbia Pl.iiiis. 



