The Rum River Valley as a Botanical District. 91 



Saskatchewan and Lake Superior basins, reaches its south- 

 ernmost limit along the western edge of Mille Lacs lake. It 

 is found abundantly in the neighborhood of the aboriginal 

 earthworks in the northwestern corner of the Indian reser- 

 vation. 



Oenothera albicaulis Nutt. reaches the easternmost limit 

 of its range in central Mille Lacs county. It is found fre- 

 quently on burnt woodlands and has doubtless been intro- 

 duced through the agency of the railroad. 



Oenothera rhombipetela Nutt. also seems to have its 

 northernmost limit in Anoka and southern Mille Lacs coun- 

 ties. In Minnesota it is characteristically a sand-dune plant. 



Pentstemon grandiBorus Nutt., Pentstemon gracilis 

 Nutt. and Penstemon pubescensSolandev are frequent in the 

 oak openings of the southern portion of the valley. 



A remarkable form, closely resembling Pentstemon albi- 

 dus Nutt., but having the open thyrse and, to a certain ex- 

 tent, the bearded lip ol Penstemon pubescens Solander., was 

 found on the sandy shores of an old lake bed west of Prince- 

 ton. The constant discovery of peculiar forms of the species 

 of Penstemon renders the genus extremely difficult to study. 



Phegopteris calcarea Fee is an interesting fern which has 

 so far only Minnesota and Iowa for its American localities. 

 In Iowa it was found near Decorah by Mr. E. W. D. Holway. 

 In Minnesota it has hitherto only been reported by Miss 

 Ellen Cathcart from the banks of the St. Louis river. I have 

 found three new localities for it in the Rum river valley. It 

 was first found on the shady banks of Farm island, in Farm 

 Island lake, about nine miles south of Aitkin. Later in the 

 season I found it growing in abundance on Robinson's island, 

 in Mille Lacs lake, and on the shady banks of Bordin's creek, 

 near Garrison, Crow Wing county. It prefers shady loca- 

 tions on the north side of high banks. 



Its near congener, Phegopteris dryopteris Fee. was also 

 found abundantly on Robinson's island and on Bassett's 

 point, near Vineland, Mille Lacs county. 



The enumeration of all the peculiar and interesting plants 

 found would be of value, but it is rather my object to point 

 out the prolific character of this narrow strip. This is due, 

 of course, to the diversity of conditions for plant sustenance. 



