ii8) VEGETATION REGIONS OF THE PRAIRIE PROVINCE 387 
ation, and the formations, briefly discussed in this article, are 
based upon a treatise entitled Zhe Phytogeography of Nebraska, 
recently published by the authors of the present paper. The data 
have been extended, however, to cover the entire prairie prov- 
ince, while in the work referred to only the territory embraced 
inthe political limits of Nebraska is considered. 
Considering Nebraska alone, the floral covering of the state 
falls into four vegetation-regions: I. Wooded bluff and meadow- 
land region; IJ. Prairie region; III. Sand hill region; IV. Foot- 
hill region. Region I consists of a narrow strip along the 
Missouri. It is an arm of the extreme western edge of the 
Alleghany forests, which projects northward into the prairie 
jtovince as far as the Great Bend of the Missouri. Although 
almost surrounded by prairies, it is in no sense a portion of the 
Pfaitie province. It is a portion of the Mississippi-basin region. 
On the central plains, especially those of Nebraska and Kansas, 
, regions II, III, and IV are well-differentiated, both topograph- 
ally and phytogeographically. As physiographic features, the 
Prairies proper (including those of Iowa and Illinois), extend- 
ng from the forest to the g8th meridian, are easily distinguished 
fom the sand hills, and the latter, finding 4 general western 
: boundary between 102-103° W., are very distinct from the 
foothills. To the south, in the Indian territory, the prairies 
per are crowded out by the sandy plains, and the prairie 
Bion disappears, leaving regions III and IV. On the Saskatch- 
obs Plains, the forests close in on the east, and the sandy 
tans drop out, resulting in a similar reduction, though here it 
tegion IIT which disappears. Isolated areas of sandy coteau 
= *oulée occur more or less frequently, however, S° that most 
of the sand hill xerophytes are represented. The more Ds pical 
les, such as are characteristic of sandy fastnesses, like the 
—"P district in Nebraska, are necessarily lacking. jac: 
a of the stronger development of region ii ts ae van 
_ ©“ and of region III to the southward, the division 0 
: Prairie Province gives to it a peculiar dovetailed pare a 
& Prairie region tapers gradually to the south, finally ¢! 
