966 MINNESOTA BOTANICAL STUDIES. 



The above list by no means includes all of the important 

 littoral plants of the Lake of the Woods region and longer 

 exploration especially on the Isles aux Sables would bring to 

 light numerous other species. Yet since equal areas were 

 covered at the different localities and the collections made with 

 equal care in all cases, it may be fairly maintained that the 

 list represents properly the varieties of dominant plants es- 

 tablished upon the four kinds of shore in question. Such a 

 list, however, gives no exact idea of the vegetation of the 

 shores it purports to cover, for the relative abundance of in- 

 dividuals is not taken into account, nor the groupings in for- 

 mations, nor robustness of growth. For example, Populus 

 tremuloides listed for Sandy beach and Isle aux Sables consti- 

 tutes an entirely different formation at the one shore as com- 

 pared with the other. Upon the dunes it appears as a loose, 

 open, scattered formation of low shrubs while at the beach it 

 forms a zone of tall trees at the back strand where the wind, 

 the waves and the ice have thrown up a ridge of sand and 

 gravel. Such a list is of interest principally because it gives 

 the student of distribution an idea what general influences have 

 acted in the population of the territory in question, and because 

 it may serve as a foundation for some of the special ecological 

 lists yet to be offered. 



Relationships of the group. — In the above list of 156 

 species, 78 or 50 per cent, are of distinctively northern range, 

 36 or 22 per cent, are of distinctively southern range, while 42 

 or 28 per cent, are of continental range and might properly be 

 counted with either group. Evidently this list of dominant 

 species indicates a generally northern character in the Lake 

 of the Woods population. But it must be remembered that 

 but very few of the plants are distinctive of high northern 

 latitudes. Excluding such forms as Juniperus sabina, Betula 

 glandulosa, Salix myrtilloides, Ribes oxycanthoides, Sorbus sam- 

 bucifolia and Arciosiaphylos uva-ursi, the remainder are in 

 large part characteristic plants of the prairies and woods of 

 Minnesota, Iowa and the Dakotas. Indeed when such a list is 

 compared with those which have been made by Arthur, Bailey 

 and Holway 5 for the Vermilion lake and Hunter's island 

 region of Lake Superior drainage, and by the writer for the 

 valley of the Minnesota 6 it is at once recognized that the 



5. Arthur. Bailey and Holway. Bull. Geol- & Nat. Hist. Sur. Minn. No. 3. 



1887. 



6. MacMillan. Metasperniae of the Minnesota valley. Rep. Bot. Sur. Minn. I. 1892. 



