The Rum River Valley as a Botanical District. 89 



north, the south, the east or the west. And we must not for- 

 get that the section under consideration has in times past 

 been subject to the same glacial action as most of our Min- 

 nesota natural drainage basijis. Furthermore, the Rum 

 river valley now lies between the old Mississippi drainage on 

 the east — the present St. Croix — and the later and present 

 channel on the west. 



Then again birds have flown, waters have carried and 

 winds blown for ages past even as they are doing to-day, all 

 assisting in the constant dissemination of seeds. 



Before enumerating some of the plants recently found in 

 this section, it would, perhaps, be well to point out some of 

 the conspicuous sylvan characteristics noted, with a view to 

 showing what a diversity of conditions and consequent mul- 

 tiplied chance for plant establishment. 



The pine-barren region characteristic around Brainerd 

 and Aitkin barely touches the northern edge of the drainage 

 north and west of Mille Lacs lake. 



The straight, slender jack pine, Pinus divaricata (Ait.) 

 Sudw., which is found in quite heavy groves in the localities 

 above mentioned, occurs only locally south to Princeton, 

 East of Mille Lacs lake miles of almost impenetrable swamp- 

 land renders botanical investigation diflicult. The timber of 

 these swamps is largely larch, Larix americana Michx. In- 

 termixed with this is to be found a considerable quantity of 

 black spruce, Picea nigra Link. 



Of course the bordering edges are of typical hard-wood 

 swamp, where maples, ashes and elms predominate. The 

 north and west shores directly contiguous to Mille Lacs lake 

 are high and abundantly covered with groves of maple, elm 

 and oak. Quite often scattered clumps of the hackberry, 

 Celtis occidentalis L., are found. 



The major part of the Mille Lacs Indian reservation is 

 covered with aluxuriantand valuable growth of pine, mostly 

 Pinus strobus L. and Pinus resinosa Ait. South of this to a 

 line a few miles north of Princeton the country is covered 

 with a thick growth of mixed timber. This formerly con- 

 tained considerable pine, but owing to the demands of civ- 

 ilization it has disappeared. Intermixed with this was a 

 valuable and interesting growth of hard-wood timber, con- 



