240 ILLINOIS ACADEMY OF SCIENCE 



oak and if possible find some indication of its ecological 

 characteristics. It might be mentioned in passing that 

 Q. alba did not fruit at all this year, and Q. bicolor 

 Willd. and Q. macrocarpa Michx, very sparingly if at 

 all. 



The region studied lies within the district surveyed by 

 Miss Simmons and reported in this volume and the parti- 

 cular portion included in this study consists of about 

 fifteen blocks in the northern part of the city of Evans- 

 ton, containing the ends of the Tolleston and Calumet 

 sand bar ridges just before they disappear owing to 

 erosion by the lake. It was intended to include the Glen- 

 wood bar in this study, but it was found that the oaks had 

 been almost entirely removed from it in this region. One 

 small patch at the Gross Point Road and Dempster 

 Street was surveyed and will be described later. 



Owing to the time when the study was begun, the acorns 

 had mostly fallen from the trees and consequently the 

 identification of the trees had to be made by an inspection 

 of the acorns as they lay on the ground. Because this 

 region is entirely built up, the acorns in many cases had 

 been removed by raking of la^vns, but even in those cases 

 it was usually possible to find a few specimens lying in 

 flower beds or in the spaces between the grass plots and 

 pavements. Great care was observed in relating the 

 acorns to the trees and in many cases it was possible to 

 state only that there were ellipsoid trees in a certain spot 

 without definitely indicating any individuals. Only speci- 

 mens showing ellipsoid characters were preserved and 

 it is possible that some were rejected which were really 

 ellipsoid so that the numbers accepted represents a min- 

 imum rather than a maximum of those really present. 



As the writer has not made much study of the ellipsoid 

 oaks and as Trelease's article (Transactions Illinois 

 Academy, Vol. XI.) is still in the printers' hands, the 

 identification of the ellipsoid varieties was a difficult task. 

 Professor Trelease very kindly assisted by identifying 

 a few type speciments which were sent to him. As is 

 known in regard to the ellipsoid oak, the acorns are ex- 

 tremely variable and the range of shape in those studied 



