PAPERS ON BOTANY 249 



No. 1161. A specimen, Xo. 1112, collected in Troy Grove, 

 Sect. 35, may be hybrid Avith Q. ellipsoidalis. 



In this and the foUowiug species the writer is glad to 

 acknowledge the assistance of Professor William Tre- 

 lease in the identification of the collections. 



7. Q. ellipsoidalis HiU, Hill's oak or Hill's black oak. 

 This species is often confounded with the preceding from 

 which it is not always easily distinguishable. Several 

 varieties have been recognized by Trelease. It seems to 

 be more plentiful in the northern half of the county and 

 was collected in the following townships : Trov Grove, 

 Sects. 11 and 18, Xos. 1101, 1106 and 1107 ; Earl, Sect. 8 

 and 17, Xos. 1120 and 1129, the latter being apparently 

 var, intermedia; Utica, Sect. 7, Xo. 1155, and Da^-ton, 

 Sect. 4, Xo. 1158. 



8. Q.imhricaria Michx., shingle oak. Found occasion- 

 ally along stream bluffs. Usually small in size. Collec- 

 tions: La Salle Township, Sect. 13, Xo. 1148, and Day- 

 ton Township, Sect. 4, Xo. 1159. 



Aesculus glabra Willd., fetid buckeye. A single speci- 

 men was found in Troy Grove Township, Xo. 1110, a few 

 scattering specimens near the to\^^l of Peru, but only 

 south of the Illinois Eiver did it become rather frequent 

 in its occurrence. 



A COMPAEISOX OF SOIL TEMPERATUEES IX 

 rPLAXD AXD BOTTOMLAXD FOEESTS 



W. B. McDoUGALL, L^XIVERSITY OF IlLIXOIS 



In connection with some ecological studies that were 

 being made on the vegetation of Vermilion County, Illi- 

 nois, during the smnmer of 1918, a series of measure- 

 ments of soil temperatures was undertaken for the pur- 

 pose of comparing habitat conditions in upland and bot- 

 tomland forests. Unforeseen events prevented this from 

 being carried out on as extensive a scale as had been in- 

 tended but it is believed that the few readings obtained 

 are worth recording in view of the fact that available 

 data on the subject are very meager. 



