PAPERS ON BOTANY 



111 



Duriu^ several seasons past, in cooperation with the 

 State Laboratory of Natural History, I have spent some 

 little time in the examination of these scarlet and ellipsoid 

 oaks as they occur in northern Illinois, and I have viewed 

 critically such herbarium material of Q. coccinca and Q. 

 clUpsoidalis as I have been able to see in herbaria, with the 

 result of finding it impossible to recognize the former 

 species in the region in which the latter occurs ; — what has 

 passed for Q. coccinca west of Lake Michigan and north of, 

 say, the lower Wabash river and the granite mountains 

 about Bismarck. Missouri, being either so-called in the 

 broader and older sense in which even Q. vchdina has 

 passed for a variety of Q. coccinca, or with reference to the 

 rounder-fruited form of Q. ellipsoidal is. 



While Qucrciis clUpsoidalis seems to be limited on the 

 east by Lake Michigan, and on the north by Lake Superior, 

 its range to the west is not closely fixed ; and, particularly, 

 I have had difficulty in finding any reason for its abrupt 

 cessation in the south. So far as evidence has been pro- 

 curable, it does not occur on or to the south of a line con- 

 necting Kankakee, LaSalle, and Rock Island, in Illinois. 

 On the other hand, it is present in quantity about Glen- 

 wood and Thornton, south of Chicago, occurs sparingly in 

 the vicinity of Joliet, is abundant on the Fox River about 

 Aurora, in the neighborhood of Samonauk, and around 

 Dixon, and it crosses the Mississippi river somewhere near 

 Fulton, Illinois, and Clinton, Iowa. Xorth of this, it is 

 found everywhere where oaks occur. 



Xo connection is apparent between the southern term- 

 ination of its range and the soil belts or glacier limits rec- 

 ognized in Illinois, and as yet it has not been found to 

 follow the larger streams, though its abundance on the 

 upper Rock River would lead one to suspect that further 

 search may reveal its presence as far south as Rock 

 Island, — where, however, I have been unable to find it. 

 Though I have seen no specimens from the upper penin- 

 sula of Michigan, it is evidently this species that Farwell* 

 reports as there becoming a large tree in the valleys but 

 reduced to a bushy shrub or small scraggy tree along rock 

 ledges, under the name Q. rubra borcalis. 



•Rep. Mich. Acad. Sci. 6 :206. 1904. 



