4 METASPERMAE OF THE MINNESOTA VALLEY. 
central river of North America, emptying its waters into the 
Gulf of Mexico. There may be distinguished then, these three 
drainage-basins, and each might be a suitable district for study 
along the lines contemplated in the establishment of a botanical 
survey. It happens however that the Mississippi drainage-area 
in Minnesota admits of a natural subdivision. The Minnesota 
river which joins the larger, but geologically newer stream, at 
Ft. Snelling, is in many ways the most interesting portion of 
the Mississippi basin. As will be shown later, in the special 
chapter devoted to this valley, the Minnesota is peculiarly 
central in its location and remarkably interesting, not only 
from its topography and situation, but on account of its history 
as well. 
Occupying the position that it does the Minnesota valley, 
while a subsidiary drainage-basin, becomes one of first import- 
ance in Minnesota. It is, therefore, the natural region which 
has been chosen for study at this time. Later, it is hoped, the 
other basins to which the superficial area of Minnesota may be 
referred, will receive attention. Thus a final report of the 
botanical survey will knit together the data acquired through 
the consecutive investigation of the different natural districts 
making up the state. For the purpose of the botanical division 
of the Geological and Natural History Survey, then, the state 
of Minnesota may be considered as presenting these divisions: 
(32). 
I. Rainy Lake river drainage-basin.............. 11,347 sq. m. 
Il. Red river drainage-basin...................... 18,106 sq. m. 
III. Lake Superior drainage-basin................. 7,689 sq. m. 
IV. Minnesota river drainage-basin............... 15,706 sq. m. 
V. Rock river drainage-basin............... 0000 1,929 sq. m. 
VI. Des Moines river drainage-basin.............. 1,639 sq. m. 
VII. Cedar River drainage-basin................... 1,206 sq. m. 
VIII. St. Croix river drainage-basin................. 3,669 sq. m. 
IX. Other tributaries of Miss. below St, Paul..... 6,399 sa. m. 
X. Central Mississippi drainage-basin............ 16,596 sq. m. 
Total area of Minnesota................00. 84,286 sq. m. 
Only the 4th and 10th of these basins are peculiarly Minne- 
sotan (disregarding the unclassified IX. div.). Of these two 
the Minnesota is much the older and more interesting area, as 
will be discussed later. 
History of botanical investigation in the Minnesota valley. 
In the earlier published works relating to the plants of Minne- 
sota it is not possible to determine accurately what references 
(8%). Hall: Physiographic Conditions of Minnesota. Proc. Hort. Soc. 393 (1884), 
